<!DOCTYPE article PUBLIC "-//NLM//DTD JATS (Z39.96) Journal Archiving and Interchange DTD v1.0 20120330//EN" "JATS-archivearticle1.dtd">
<article xmlns:xlink="http://www.w3.org/1999/xlink">
  <front>
    <journal-meta>
      <journal-title-group>
        <journal-title>K. (2011). Export Restrictions and Price Insulation during Commodity
Price Booms. American Journal of Agricultural Economics</journal-title>
      </journal-title-group>
    </journal-meta>
    <article-meta>
      <article-id pub-id-type="doi">10.1093/ajae</article-id>
      <title-group>
        <article-title>Enhancing Wheat Price Forecasting Accuracy through Prophet Based Models⋆</article-title>
      </title-group>
      <contrib-group>
        <contrib contrib-type="author">
          <string-name>Dmytro Zherlitsyn</string-name>
          <email>d.zherlitsyn@unwe.bg</email>
          <xref ref-type="aff" rid="aff2">2</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Volodymyr Kharchenko</string-name>
          <xref ref-type="aff" rid="aff1">1</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Hanna Kharchenko</string-name>
          <xref ref-type="aff" rid="aff0">0</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Seasonality</string-name>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Trend</string-name>
          <xref ref-type="aff" rid="aff2">2</xref>
        </contrib>
        <aff id="aff0">
          <label>0</label>
          <institution>Glasgow Caledonian University</institution>
          ,
          <addr-line>G4 0BA, Glasgow</addr-line>
          ,
          <country country="UK">UK</country>
        </aff>
        <aff id="aff1">
          <label>1</label>
          <institution>National University of Life and Environmental Science of Ukraine</institution>
          ,
          <addr-line>03189 Kyiv</addr-line>
          ,
          <country country="UA">Ukraine</country>
        </aff>
        <aff id="aff2">
          <label>2</label>
          <institution>University of National and World Economy</institution>
          ,
          <addr-line>1303 Sofia</addr-line>
          ,
          <country country="BG">Bulgaria</country>
        </aff>
      </contrib-group>
      <pub-date>
        <year>2021</year>
      </pub-date>
      <volume>227</volume>
      <issue>1</issue>
      <fpage>0000</fpage>
      <lpage>0002</lpage>
      <abstract>
        <p>Accurate forecasting of agricultural commodity prices, especially wheat prices, is critical for stabilizing food markets and informing strategic decisions across supply chains. This study investigates optimal forecasting methodologies for wheat prices using Facebook's Prophet Tool. While Prophet's default configuration uses base forecasting patterns, its performance is significantly enhanced through hyperparameter optimization, including custom Fourier terms for crop-specific seasonality and adaptive changepoint detection to capture market shocks. To address residual volatility during geopolitical or climatic disruptions, the proposed framework integrates Prophet with gradient boosting algorithms for error correction, forming a hybrid model. The hybrid Prophet-ML approach further improves the accuracy of forecasting models. Empirical results, quantified through MAE, RMSE, and mean absolute percentage error (MAPE) metrics, underscore the framework's robustness in reconciling structural time series patterns with nonlinear market dynamics.</p>
      </abstract>
      <kwd-group>
        <kwd>eol&gt;Wheat prices</kwd>
        <kwd>Prophet</kwd>
        <kwd>Forecasting</kwd>
        <kwd>Machine learning</kwd>
        <kwd>Time series</kwd>
        <kwd>Hyperparameter tuning</kwd>
        <kwd>Price volatility</kwd>
      </kwd-group>
    </article-meta>
  </front>
  <body>
    <sec id="sec-1">
      <title>1. Introduction</title>
      <p>Accurate forecasting is a key problem of socio and economic analysis. It enables understanding
development trends, risk assessment, and preparation for potential changes across economic sectors.
In the globalization and IT era, economic instability and rapid technological shifts, effective
forecasting underpins strategic decision-making at governmental, corporate, and societal levels,
fostering stability, innovation, and adaptability to future challenges.</p>
      <p>
        Forecasting market indicators, particularly resource and commodity prices, is vital for economic
development. Agricultural commodities such as wheat are core information about global food market
trends, and price fluctuations significantly support and impact economies. Accurate price forecasting
enhances production cycle management, trade potential evaluation, and price stabilization policies
[
        <xref ref-type="bibr" rid="ref15">15</xref>
        ].
      </p>
      <p>Contemporary analytical methods, including machine learning, econometric models, and
specialized algorithms, improve forecasts' accuracy, reliability, and efficiency. Socio and economic
data forecasting requires robust mathematical and statistical models capable of predicting market
indicators, such as agricultural prices, in complex and dynamic environments.</p>
      <p>
        Prophet, a time series forecasting tool developed by Meta (formerly Facebook), integrates
statistical power with the ability to handle seasonal and irregular fluctuations characteristic of
socioeconomic processes [
        <xref ref-type="bibr" rid="ref16">16</xref>
        ].
      </p>
      <p>Thus, forecasting is an analytical tool and a foundation for formulating policies and corporate
strategies to ensure stability, sustainable development, and economic growth.</p>
      <p>
        Prophet is a time series forecasting tool developed by Meta (formerly Facebook), specifically
designed to handle datasets exhibiting seasonality, trend patterns, and irregularities such as missing
values or anomalies - typical characteristics of socio-economic processes [31]. The library integrates
seamlessly with Python and R programming ecosystems, offering compatibility with interactive
environments like Jupyter Notebook for data visualization, cloud based platforms such as Google
Colab for code execution without local setup, and integrated development environments (IDEs) like
PyCharm, VSCode, and Spyder for advanced implementations. Prophet is typically used alongside
foundational Python libraries, including Pandas for data manipulation, NumPy for numerical
computations, and Matplotlib for visualization [
        <xref ref-type="bibr" rid="ref10 ref9">9, 10, 21, 25, 36</xref>
        ].
      </p>
      <p>
        While Prophet provides a robust framework for forecasting, other methodologies remain relevant
in socio-economic analysis. For instance, the ARIMA (AutoRegressive Integrated Moving Average)
model is a classical approach that is practical for datasets with linear trends and seasonal components
but is limited in handling complex seasonality or external shocks [
        <xref ref-type="bibr" rid="ref3">3</xref>
        ]. Linear regression and its
variants are widely used to model relationships between variables, such as commodity prices and
macroeconomic indicators, enabling the quantification of external factor impacts [
        <xref ref-type="bibr" rid="ref11">11</xref>
        ]. Machine
learning techniques, including Random Forest, Gradient Boosting, and Support Vector Machines
(SVM), excel in capturing non-linear interactions among multiple variables, particularly in
largescale datasets [27]. Factor models, which assess price dynamics through influential variables like
climatic conditions or market demand-supply shifts, further complement these approaches [
        <xref ref-type="bibr" rid="ref18 ref2">2, 18</xref>
        ].
      </p>
    </sec>
    <sec id="sec-2">
      <title>2. Literature Review</title>
      <p>Forecasting represents a critical analytical tool for understanding social and economic trends,
assessing risks, and preparing for systemic changes. Time series forecasting has evolved significantly
by integrating machine learning techniques and specialized tools like Facebook’s Prophet, which
address limitations inherent in traditional econometric methods.</p>
      <p>
        Adhikari and Agrawal [
        <xref ref-type="bibr" rid="ref1">1</xref>
        ] provide a foundational framework for time series modelling,
emphasizing the need for adaptable approaches in handling complex datasets. Building on this,
Taylor and Letham [32] introduced Prophet, an open-source tool designed to model trends,
seasonality, and external factors in socio and economic data. Its robustness in handling missing
values and irregular intervals has been validated across diverse applications, from financial markets
to public health crises. For instance, Zivot and Wang [37] highlight the challenges of modelling
volatile financial time series, while Martin and Anderson [20] demonstrate the critical role of price
forecasting in mitigating agricultural market disruptions caused by export restrictions.
      </p>
      <p>
        The limitations of classical methods like ARIMA in managing noisy, large-scale datasets have
driven interest in machine learning. Lim and Zohren [
        <xref ref-type="bibr" rid="ref17">17</xref>
        ] survey deep learning applications in time
series forecasting, noting their capacity to uncover non-linear patterns without prior assumptions.
Gupta et al. [
        <xref ref-type="bibr" rid="ref8">8</xref>
        ] extend this to agricultural economics, showing how machine learning models capture
external factor influences on commodity prices. Prophet’s practical utility is further evidenced by
Parsa et al. [26], who combine it with anomaly detection for industrial time series analysis, and
Menculini et al. [
        <xref ref-type="bibr" rid="ref7">7, 23</xref>
        ], who demonstrate its competitive performance against ARIMA and deep
learning in food price forecasting.
      </p>
      <p>
        Recent applications underscore Prophet’s versatility. Hossain et al. [22] apply it to predict
catchment-level rainfall using climate model data in environmental science. Shen et al. [
        <xref ref-type="bibr" rid="ref12">12</xref>
        ] adapted it
for multi-pollutant air quality forecasting in Seoul. Angelo et al. [24] highlight its superiority over
ARIMA in Bitcoin price prediction, attributing this to its handling of volatility. Public health
implementations include Satrio et al. [
        <xref ref-type="bibr" rid="ref4">4</xref>
        ] and Sah et al. [29], who use Prophet for COVID-19 case
forecasting, proposing hybrid models to improve accuracy.
      </p>
      <p>
        Agricultural economics studies reveal Prophet’s sector-specific value. Kharchenko et al. [
        <xref ref-type="bibr" rid="ref13 ref14">13, 14</xref>
        ]
focus on investment forecasting for Ukrainian agribusinesses, while Kostaridou et al. [
        <xref ref-type="bibr" rid="ref16">16</xref>
        ] compare
their performance with traditional models in Greek tomato markets. In transportation, Agyemang et
al. [
        <xref ref-type="bibr" rid="ref5">5</xref>
        ] integrate change point detection for accident prediction, and Saeed et al. [28] apply it to
container freight rate forecasting.
      </p>
      <p>Emerging applications in energy systems [34] and network traffic management [35] further
demonstrate Prophet’s adaptability. These studies affirm that combining mathematical rigor with
modern computational tools enhances forecasting precision, enabling data-driven decision making
across economic, environmental, and public health domains.</p>
      <p>Contemporary research underscores the significance of integrating mathematical approaches
with advanced technologies in forecasting socio-economic processes. Combining robust statistical
methods and innovative computational tools like Prophet enhances forecasting accuracy, reliability,
and practicality. Integrating advanced forecasting techniques provides valuable support for strategic
decision-making, enabling stakeholders to manage economic, environmental, and public health
challenges proactively. However, future studies should focus on the practical application of the
methods and tools, e.g., Prophet Python Forecasting tools, to robust analytical results, improve
accuracy, and respond to global uncertainties.</p>
      <p>Thus, this study aims to forecast wheat prices using a combination of Prophet and machine
learning tools, focusing on assessing their performance in modelling complex dynamic trends.</p>
    </sec>
    <sec id="sec-3">
      <title>3. Methodology</title>
      <p>
        This study utilizes the Federal Reserve Economic Data (FRED) source. These platforms provide
complementary data streams essential for analysing agricultural commodity price dynamics. FRED
(Federal Reserve Economic Data), maintained by the Federal Reserve Bank of St. Louis, offers access
to over 700,000 economic and financial indicators, including historical prices for key agricultural
commodities such as wheat. These data are critical for identifying long-term market trends and
volatility patterns [
        <xref ref-type="bibr" rid="ref6">6</xref>
        ].
      </p>
      <p>
        Daily wheat price data in USD per kilogram are sourced from Markets Insider, a comprehensive
financial news platform offering real-time and historical market data essential for capturing
shortterm market fluctuations and providing granular insights into price movements [
        <xref ref-type="bibr" rid="ref19">19</xref>
        ].
      </p>
      <p>The dataset analysed in the paper covers wheat prices from two periods: monthly price records
from January 1990 to November 2024 and daily price records from January 2014 to January 2025. Data
preprocessing steps included standardizing date formats and addressing missing values.</p>
      <p>The descriptive statistics for the wheat price dataset, providing insights into the central
tendencies, variability, and distribution characteristics of the prices, are summarized in Table 1.</p>
      <p>The descriptive statistics (Table 1) show several notable characteristics of wheat prices over the
observed periods. From 1990 to 2024, monthly wheat prices show an average price of approximately
160.66 USD per metric ton, with a median slightly lower at 151.80 USD, indicating a mild positive
skewness (1.00). The relatively high standard deviation (67.46) suggests considerable variability in
monthly wheat prices over the long-term period. Kurtosis near zero (0.07) indicates that the
distribution of monthly prices is near normal, with neither pronounced peaks nor extreme outliers.</p>
      <p>Daily wheat prices, observed from 2014 to 2025, exhibit a higher average price of 209.50 USD per
metric ton, with a median of 194.50 USD per kg, further suggesting skewness (1.15) and a noticeable
deviation from the monthly averages. The daily dataset has a higher kurtosis (2.94), indicating a
heavier tail distribution with more frequent price spikes or drops. The range (298.25) with a minimum
of 140.00 USD and a maximum of 438.25 USD indicates significant price volatility within the daily
measured period.</p>
      <p>The distributional differences between series have important implications for forecasting. The
monthly data's near-normal distribution and lower kurtosis suggest it may be more suitable for
traditional time series models that assume Gaussian errors. However, the daily series' properties and
higher skewness indicate that models accounting for fat tails and asymmetric distributions might be
more appropriate for short-term forecasting. Thus, our subsequent analysis will also compare the
predictive performance of both series to determine their relative forecasting merits under different
market conditions.</p>
      <p>To achieve the research aim, the authors employed a comprehensive methodological approach
based on the classical Prophet framework for time series analysis. The Prophet library utilizes
mathematical models that combine trend, seasonality, and holiday effects for time series forecasting.
The general forecasting model in Prophet can be expressed as [30, 33]:</p>
      <p>y (t )=g (t )+ s (t )+h (t )+ ϵ t
where:
y (t ) is the forecast value at time t ;
g (t ) is the trend component (long-term change);
s (t ) is the seasonal component (cyclic variations such as annual or weekly fluctuations);
h (t ) captures holiday effects (impact of special events or holidays);
ϵ t is random error (noise or uncertainty in the data) .</p>
      <p>The trend component in Prophet can be modeled either as linear [30, 33]:</p>
      <p>() = 0 + 1
where:
β0 is the initial trend level β1 indicates the trend change rate or as logistic growth:
g (t )=</p>
      <p>C
1+exp ⁡(−( β0+ β1 t ))
where:
C is the maximum trend level (carrying capacity),
β0 is the trend offset,
(1)
(2)
(3)
β1 represents the growth rate t is the time factor.</p>
      <p>The logistic trend proves particularly valuable for modelling processes with natural limits (e.g.,
maximum production capacities).</p>
      <p>Seasonal components are modeled using Fourier series decomposition [30, 33]:</p>
      <p>K 2 πkt 2 πkt
s (t )=∑ ( ak cos( )+bk sin( ))</p>
      <p>k=1 P P
where:
P is the seasonal period (e.g., P=365 for yearly seasonality);
akand bk are coefficients determining the amplitude and phase of seasonality for each harmonic k;
k represents the number of harmonics used to model seasonality.</p>
      <p>This decomposition effectively captures seasonal patterns (annual, weekly, etc.).</p>
      <p>Holiday effects may be modelled through additional parameters [30, 33]:
(4)
(5)
(6)</p>
      <p>M
h (t )=∑ I ( t , j ) δ j</p>
      <p>j=1
ϵ t N ( 0 , σ 2 )
where:
I ( t , j ) is an indicator function (1 if time t corresponds to holiday j, 0 otherwise)
δ j represents the effect size for holiday j
The error component ∈ t is typically modelled as normally distributed [30, 33]:
where σ² error’s variance.</p>
      <p>It should be noted that for Prophet object, parameter estimation is typically performed using
maximum likelihood estimation (MLE). This approach optimizes model parameters by maximizing
the likelihood of observed data, ensuring reliable trend and seasonality detection. The resulting
model demonstrates robust forecasting capabilities, effectively handling seasonal variations, holiday
effects, and underlying trends in the data.</p>
    </sec>
    <sec id="sec-4">
      <title>4. Results and Discussion</title>
      <p>The study's first stage aims to evaluate the performance of Facebook's Prophet algorithm for
forecasting monthly wheat prices (USD/ton) from 1992 to 2024. Three modelling approaches were
implemented to address the challenges of agricultural commodity price prediction: a baseline model
with default parameters, a customized model incorporating domain-specific adjustments, and a
hyperparameter-optimized model. The analysis focuses on the comparative performance of these
approaches, with particular emphasis on their ability to capture structural trends, seasonal patterns,
and exogenous shocks inherent to global wheat markets.</p>
      <p>Model 1. Prophet modelling object with default Parameters produced unsatisfactory results,
failing to account for the dataset’s unique characteristics. Visual inspection revealed systematic
deviations between predicted and observed values. The model inadequately captured long-term price
trends and intra-annual cyclicality, resulting in a mean absolute percentage error (MAPE) exceeding
20% during validation. This poor performance stemmed from inappropriate assumptions about
seasonality components and insufficient flexibility.</p>
      <p>Model 2. Customized Parameterization of the Prophet() object is as follows:



</p>
      <p>Disabling irrelevant daily and weekly seasonality while preserving annual periodicity;
Explicit specification of monthly cycles (30.5-day period, Fourier order=5);
Enhanced changepoint detection (n=60) to better reflect historical market shocks;
Annual seasonality modelling using 12 Fourier terms to capture, for example,
plantingharvest cycles.</p>
      <sec id="sec-4-1">
        <title>These adjustments improved model fidelity substantially (Figure 1).</title>
        <p>Key performance metrics of the Model 2 demonstrate marked enhancement:
MAPE reduced to 11%
RMSE decreased to $30.82/ton
R² increased to 0.79</p>
        <p>The customized model identified major price dynamics, including decadal-scale inflation trends
and biennial production cycles. However, residual analysis revealed persistent underestimation of
extreme price spikes during geopolitical crises, suggesting opportunities for further refinement
through exogenous variable integration.</p>
        <p>Model 3. Optimized Hyperparameters of the Prophet() object. The study employed a grid search
approach to systematically evaluate combinations of key parameters, including the trend flexibility
parameter (changepoint_prior_scale), seasonality formulation (seasonality_mode), and Fourier
orders for yearly and monthly seasonal components. The optimal configuration identified
changepoint_prior_scale=0.5, seasonality_mode='multiplicative', and Fourier orders of 12 (yearly)
and 15 (monthly) - reflects the inherent complexities of wheat price dynamics. The high
changepoint_prior_scale value suggests substantial variability in trend shifts. Multiplicative
seasonality scales seasonal effects with the trend magnitude. It aligns with the observed amplification
of price fluctuations during periods of high market volatility, such as harvest cycles or export
restrictions.</p>
        <p>The result of the hyperparameter optimization defines the following:
‘changepoint_prior_scale': 0.5,
'seasonality_mode': 'multiplicative',
'yearly_fourier_order': 12,
'monthly_fourier_order': 15.</p>
        <p>For example, a yearly Fourier order of 12 captures nuanced annual seasonality, potentially linked
to planting and harvesting schedules; the monthly order of 15 accommodates irregular short-term
variations, such as mid-month price adjustments due to policy changes or speculative trading.</p>
        <p>The results of the Model 3 application are shown in Figure 2.</p>
      </sec>
      <sec id="sec-4-2">
        <title>Key performance metrics of the Model 3 are: MAPE reduced to 9% RMSE decreased to $24.81/ton R² increased to 0.87</title>
        <p>Comparative analysis with previously estimated Prophet configurations revealed that the
optimized model reduced the mean absolute percentage error (MAPE) to 9%. The model’s coefficient
of determination (R² = 0.87) further demonstrates its ability to explain 87% of the variance in
historical wheat prices, underscoring the efficacy of hyperparameter tuning. Despite these
advancements, residual errors persist, as evidenced by a root mean squared error (RMSE) of 24.81
USD/tn. These residuals highlight some of Prophet’s limitations in modelling data fluctuation, a
common feature of agricultural and other markets where volatility during periods of uncertainty,
such as droughts, trade restrictions, wars, and so on. For instance, the model underestimates price
spikes observed during 2008 (global financial crisis) and 2022 (agricultural export restrictions from
Russia), characterized by abrupt variance shifts. The lack of the Prophet tools can be solved using a
hybrid framework. For example, integrating Prophet with classical Machine learning models is
proposed to address this gap. This approach will be discussed later.</p>
        <p>The second phase of this investigation focused on analysing daily wheat price data (see Table 1).</p>
        <p>Model 4. A customized Prophet model configuration was implemented to capture the inherent
patterns in high-frequency agricultural commodity markets (based on monthly data hyperparameter
tests). The model was initialized with yearly seasonality explicitly disabled, as preliminary tests
indicated that intra-year patterns were better captured through manually specified Fourier terms
rather than the default approximation of annual seasonality. Weekly and daily seasonal components
were also deactivated, as their inclusion did not improve model performance and risked introducing
noise in the daily price forecasting context.</p>
        <p>The changepoint prior scale parameter was set to 5.0 to enhance the model's sensitivity to abrupt
trend changes. This modification allowed the model to better adapt to structural breaks in the price
series while maintaining robustness against overfitting.</p>
        <p>The seasonal components were explicitly modelled through custom Fourier series expansions. A
yearly seasonality term of 365.25 days and a Fourier order of 12 were incorporated to account for
annual cyclical patterns. Additionally, a monthly seasonality component with a period of 30.5 days
and a Fourier order of 5 was included to capture finer-grained periodic fluctuations potentially linked
to mid-month market adjustments.</p>
        <p>The results of the Model 4 application are depicted in Figure 3.</p>
      </sec>
      <sec id="sec-4-3">
        <title>Key performance metrics of the Model 4 are: MAPE: 5% RMSE: 14.40 USD/kg R²: 0.93</title>
        <p>Figure 3 shows that the price trajectory exhibits fluctuations, characteristic of agricultural
commodities influenced by short-term supply-demand imbalances, climatic variability, and
geopolitical events. Notably, the model captures a steady upward trend from 2020 to mid-2022. The
forecasted values beyond 2024 suggest a stabilization phase. However, the actual price fluctuation is
high.</p>
        <p>Model 4, configured with custom-defined parameters, demonstrates significant improvements in
forecasting accuracy relative to monthly data models. Although daily data are less consistent with
the normal statistical distribution, the Prophet's tools can be used for forecasting with higher
accuracy. This is most likely due to the tool's settings focused on recording daily changes. At the
same time, intra-month interpolation is used in monthly forecasts. However, analysis of Figure 3
shows that Model 4 also does not cope very well with periods of high volatility and sudden changes in
trends (after 2024). That is why we will consider the hybrid approach, which uses machine learning
models for the model's residuals.</p>
        <p>Model 5 integrates the Prophet model (customized for daily data in Model 4) with a machine
learning-based residual correction mechanism. Residuals from Model 4 — representing unexplained
variance — were estimated using a stacked ensemble of gradient-boosting algorithms (XGBoost,
LightGBM, and CatBoost), meta-learned through a Ridge regression model. This approach leverages
the complementary strengths of Prophet’s structural time series decomposition and the ensemble’s
capacity to model nonlinear, high-frequency noise.</p>
        <p>Figure 4 illustrates the daily wheat price dynamics from 2016 to 2024, comparing observed values,
Prophet-based forecasts (Model 4), and adjusted forecasts generated by a hybrid Prophet-ML
framework (Model 5).</p>
        <p>The hybrid model achieved a mean absolute percentage error (MAPE) of 8.1% and an R² score of
0.84. While these metrics suggest a marginal increase in MAPE compared to Model 4 (MAPE = 5%, R²
= 0.93), the hybrid framework demonstrates better performance in capturing transient volatility, as
evidenced by its alignment with extreme price movements in Figure 4.</p>
        <p>Thus, Model 5 represents a pragmatic advancement in agricultural price forecasting, addressing
Prophet’s limitations in volatility capture through machine learning-driven residual correction.
While its MAPE suggests modest degradation in overall accuracy, its ability to replicate
highfrequency fluctuations provides actionable insights for stakeholders navigating volatile markets.</p>
        <p>Discussion. For further discussion, the authors applied Python AutoARIMA,
RandomForestRegressor, XGBRegressor tools, as described in [36], to the same data sets. Comparison
with the results reveals that the new Prophet-based models deliver superior performance over
classical approaches. Classical AutoARIMA yielded a MAPE of 12.29% for monthly data and a
negative R² (-2.11). A Random Forest model improved the accuracy (MAPE 9.37%) and achieved a
modest R² of 0.23. In contrast, the optimized Prophet model in our study attained a substantially
lower MAPE (9%) and a high R² of 0.87, indicating a dramatic gain in both accuracy and explanatory
power. The advantage of the Prophet's complex approach is even more pronounced for daily
forecasts. The AutoARIMA baseline on daily prices produced substantial errors (MAPE 34.67%) with
no predictive power (R² ≈ -10.02). Even an ensemble machine learning method (Random Forest +
XGBoost) achieved only a MAPE of 8.71%, with R² still negative at -0.36. By contrast, the new hybrid
Prophet-ML model maintained a comparably low MAPE while boosting R² to 0.93, reflecting superior
accuracy and a much-improved ability to capture variance and volatility in wheat prices. These
results demonstrate that the hybrid approach offers significantly enhanced forecasting accuracy and
robustness, especially under volatile market conditions, compared to classical ARIMA and standalone
ML benchmarks. The substantial error reduction and improved R² in the Prophet-ML forecasts
further validate the proposed methodology and underscore the practical value of integrating Prophet
with machine-learning-based residual correction for reliable wheat price forecasting.</p>
        <p>However, it should be noted that classical forecasting models [36] were used without
hyperparameter optimization and did not use neural network models (like LSTM), which determines
further study directions. However, it should also be noted that approaches based on Prophet models
combine relatively high accuracy, simplicity, clarity, and interpretability of the result, further
increasing their practical value. For example, although LSTM models often give more accurate
forecasts, they are challenging to interpret practically.</p>
      </sec>
    </sec>
    <sec id="sec-5">
      <title>Conclusion</title>
      <p>Accurate forecasting of agricultural commodity prices remains pivotal for economic stability, policy
formulation, and strategic decision-making in volatile markets. This study evaluated the efficacy of
Facebook’s Prophet algorithm in modelling wheat price dynamics across monthly (1990–2024) and
daily (2014–2025) datasets, emphasizing customization and integration with machine learning (ML)
to address inherent limitations.</p>
      <p>Key findings demonstrate that Prophet’s default configuration is unsuitable for agricultural
market structural trends and seasonal patterns. However, tailored parameterization—such as
adjusting Fourier terms for seasonality, optimizing changepoint detection, and employing
multiplicative seasonality—significantly enhanced performance. For monthly data, hyperparameter
tuning reduced MAPE to 9% and improved R² to 0.87, while daily forecasting achieved a MAPE of 5%
and R² of 0.93. Despite these advancements, residual errors during extreme events (e.g., geopolitical
crises, financial crises, and so on) underscore Prophet’s challenges in capturing abrupt volatility.</p>
      <p>The hybrid Prophet-ML framework addressed this gap by leveraging gradient-boosting ensembles
to correct residuals, improving alignment with high-frequency fluctuations. Although marginally
increasing MAPE to 8.1%, the hybrid model better replicated transient price spikes, offering
actionable insights for stakeholders navigating volatile markets.</p>
      <p>These results highlight Prophet’s adaptability across temporal resolutions but emphasize the
necessity of domain-specific customization and complementary ML integration. Limitations persist
in modelling exogenous shocks (e.g., droughts, trade wars), suggesting the need for incorporating
external variables (e.g., climate data, policy changes) in future work. Further research could explore
advanced ML architectures, real-time data integration, and cross-commodity analyses to bolster
predictive robustness.</p>
      <p>In conclusion, this study demonstrates the practical applicability of the Prophet model as a
scalable tool for forecasting agricultural commodity prices, particularly wheat. The results emphasize
the benefits of integrating Prophet with machine learning methods, where the hybrid approach
improves the model’s ability to capture volatility and nonlinear market dynamics. Nevertheless,
despite the substantial enhancement in predictive accuracy, certain limitations remain, particularly
considering external factors such as weather anomalies, political interventions, and global supply
chain disruptions. Addressing these challenges requires including exogenous variables and applying
advanced deep learning models, such as LSTM networks, capable of modelling long-term
dependencies in complex time series data. At the same time, balancing predictive accuracy with
model interpretability is essential to ensure practical applicability in decision-making processes.
Further research should also focus on developing dynamic weighting mechanisms that optimize the
trade-off between trend stability and sensitivity to abrupt market changes, as well as the systematic
application of cross-validation techniques to improve the robustness of forecasting models.</p>
    </sec>
    <sec id="sec-6">
      <title>Declaration on Generative AI</title>
      <p>While preparing this work, the authors used GPT-4 and Grammarly tools to check grammar and
spelling. After using these tools, they reviewed and edited the content as needed and took full
responsibility for the publication’s content.</p>
    </sec>
  </body>
  <back>
    <ref-list>
      <ref id="ref1">
        <mixed-citation>
          [1]
          <string-name>
            <surname>Adhikari</surname>
            ,
            <given-names>R.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Agrawal</surname>
            ,
            <given-names>R.K.</given-names>
          </string-name>
          <article-title>An Introductory Study on Time Series Modelling and Forecasting</article-title>
          . p.
          <volume>67</volume>
          arXiv (
          <year>2013</year>
          ), https://doi.org/10.48550/arXiv.1302.6613
        </mixed-citation>
      </ref>
      <ref id="ref2">
        <mixed-citation>
          [2]
          <string-name>
            <surname>Bai</surname>
            ,
            <given-names>J.</given-names>
          </string-name>
          , &amp;
          <string-name>
            <surname>Ng</surname>
            ,
            <given-names>S.</given-names>
          </string-name>
          (
          <year>2008</year>
          ).
          <article-title>Forecasting economic time series using targeted predictors</article-title>
          .
          <source> Journal of Econometrics</source>
          , 
          <volume>146</volume>
          (
          <issue>2</issue>
          ),
          <fpage>304</fpage>
          -
          <lpage>317</lpage>
          . https://doi.org/10.1016/j.jeconom.
          <year>2008</year>
          .
          <volume>08</volume>
          .010
        </mixed-citation>
      </ref>
      <ref id="ref3">
        <mixed-citation>
          [3]
          <string-name>
            <surname>Box</surname>
            ,
            <given-names>G. E.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Jenkins</surname>
            ,
            <given-names>G. M.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Reinsel</surname>
            ,
            <given-names>G. C.</given-names>
          </string-name>
          , &amp;
          <string-name>
            <surname>Ljung</surname>
            ,
            <given-names>G. M.</given-names>
          </string-name>
          (
          <year>2015</year>
          ).
          <article-title> Time series analysis: Forecasting and control (5th ed</article-title>
          .). John Wiley &amp; Sons.
        </mixed-citation>
      </ref>
      <ref id="ref4">
        <mixed-citation>
          [4]
          <string-name>
            <given-names>Christophorus</given-names>
            <surname>Beneditto Aditya Satrio</surname>
          </string-name>
          ,
          <string-name>
            <given-names>William</given-names>
            <surname>Darmawan</surname>
          </string-name>
          , Bellatasya Unrica Nadia, Novita
          <string-name>
            <surname>Hanafiah</surname>
          </string-name>
          (
          <year>2021</year>
          )
          <article-title>Time series analysis and forecasting of coronavirus disease in Indonesia using ARIMA model and</article-title>
          PROPHET Procedia Computer Science Volume
          <volume>179</volume>
          ,
          <string-name>
            <surname>Pages</surname>
          </string-name>
          524-532 https://doi.org/10.1016/j.procs.
          <year>2021</year>
          .
          <volume>01</volume>
          .036
        </mixed-citation>
      </ref>
      <ref id="ref5">
        <mixed-citation>
          [5]
          <string-name>
            <surname>Edmund</surname>
            <given-names>F.</given-names>
          </string-name>
           Agyemang, Joseph A. Mensah, Eric Ocran, Enock Opoku,
          <string-name>
            <given-names>Ezekiel N.N.</given-names>
             
            <surname>Nortey</surname>
          </string-name>
          (
          <year>2023</year>
          )
          <article-title>Time series based road traffic accidents forecasting via SARIMA and Facebook Prophet model with potential change points</article-title>
          ,
          <source>Heliyon</source>
          , Vol.
          <volume>9</volume>
          ,
          <string-name>
            <surname>Issue</surname>
            <given-names>12</given-names>
          </string-name>
          , e22544 doi: 
          <volume>10</volume>
          .1016/j.heliyon.
          <year>2023</year>
          .e22544
        </mixed-citation>
      </ref>
      <ref id="ref6">
        <mixed-citation>
          [6]
          <string-name>
            <given-names>Federal</given-names>
            <surname>Reserve</surname>
          </string-name>
          <article-title>Bank of St. Louis. (n.d.). FRED Economic Data</article-title>
          . https://fred.stlouisfed.org/
        </mixed-citation>
      </ref>
      <ref id="ref7">
        <mixed-citation>
          [7]
          <string-name>
            <surname>Furtado</surname>
            ,
            <given-names>P.</given-names>
          </string-name>
          (
          <year>2021</year>
          ).
          <article-title>Epidemiology SIR with Regression, Arima,</article-title>
          and Prophet in Forecasting Covid-
          <volume>19</volume>
          . Engineering Proceedings,
          <volume>5</volume>
          (
          <issue>1</issue>
          ), 52. https://doi.org/10.3390/engproc2021005052
        </mixed-citation>
      </ref>
      <ref id="ref8">
        <mixed-citation>
          [8]
          <string-name>
            <surname>Gupta</surname>
            ,
            <given-names>S.</given-names>
          </string-name>
          , et al. (
          <year>2020</year>
          ).
          <article-title>Machine Learning Models for Predicting Agricultural Commodity Prices</article-title>
          .
          <source>Journal of Agricultural Economics</source>
          ,
          <volume>71</volume>
          (
          <issue>3</issue>
          ),
          <fpage>432</fpage>
          -
          <lpage>450</lpage>
          .
        </mixed-citation>
      </ref>
      <ref id="ref9">
        <mixed-citation>
          [9]
          <string-name>
            <surname>Harris</surname>
            ,
            <given-names>C. R.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Millman</surname>
            , K. J., van der Walt,
            <given-names>S. J.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Gommers</surname>
            ,
            <given-names>R.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Virtanen</surname>
            ,
            <given-names>P.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Cournapeau</surname>
            ,
            <given-names>D.</given-names>
          </string-name>
          , ... &amp;
          <string-name>
            <surname>Oliphant</surname>
            ,
            <given-names>T. E.</given-names>
          </string-name>
          (
          <year>2020</year>
          ).
          <article-title>Array programming with NumPy</article-title>
          . Nature, 
          <volume>585</volume>
          (
          <issue>7825</issue>
          ),
          <fpage>357</fpage>
          -
          <lpage>362</lpage>
          . https://doi.org/10.1038/s41586-020-2649-2
        </mixed-citation>
      </ref>
      <ref id="ref10">
        <mixed-citation>
          [10]
          <string-name>
            <surname>Hunter</surname>
            ,
            <given-names>J. D.</given-names>
          </string-name>
          (
          <year>2007</year>
          ).
          <article-title>Matplotlib: A 2D graphics environment</article-title>
          . Computing in Science &amp; Engineering, 
          <volume>9</volume>
          (
          <issue>3</issue>
          ),
          <fpage>90</fpage>
          -
          <lpage>95</lpage>
          . https://doi.org/10.1109/
          <string-name>
            <surname>MCSE</surname>
          </string-name>
          .
          <year>2007</year>
          .55
        </mixed-citation>
      </ref>
      <ref id="ref11">
        <mixed-citation>
          [11]
          <string-name>
            <surname>James</surname>
            ,
            <given-names>G.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Witten</surname>
            ,
            <given-names>D.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Hastie</surname>
            ,
            <given-names>T.</given-names>
          </string-name>
          , &amp;
          <string-name>
            <surname>Tibshirani</surname>
            ,
            <given-names>R.</given-names>
          </string-name>
          (
          <year>2013</year>
          ).
          <article-title> An introduction to statistical learning </article-title>
          (Vol.
          <volume>112</volume>
          ). Springer.
        </mixed-citation>
      </ref>
      <ref id="ref12">
        <mixed-citation>
          [12]
          <string-name>
            <surname>Justin</surname>
            <given-names>Shen</given-names>
          </string-name>
          , Davesh Valagolam,
          <string-name>
            <surname>Serena McCalla</surname>
          </string-name>
          (
          <year>2020</year>
          )
          <article-title>Prophet forecasting model: a machine learning approach to predict the concentration of air pollutants (PM2.5, PM10, O3, NO2, SO2</article-title>
          , CO) in Seoul,
          <source>South Korea</source>
          <volume>8</volume>
          (
          <issue>3</issue>
          ):e9961 doi:10.7717/peerj.9961
        </mixed-citation>
      </ref>
      <ref id="ref13">
        <mixed-citation>
          [13]
          <string-name>
            <surname>Kharchenko</surname>
            <given-names>H.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Kharchenko</surname>
            <given-names>V.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Malak-Rawlikowska</surname>
            <given-names>A</given-names>
          </string-name>
          . (
          <year>2018</year>
          ).
          <article-title>Investment expenditures in Ukrainian agricultural enterprises: prognosis and development of appropriate investment strategy</article-title>
          .
          <source>Roczniki Naukowe Ekonomii Rolnictwa i Rozwoju Obszarów Wiejskich</source>
          <volume>105</volume>
          (
          <issue>2</issue>
          ), pp.
          <fpage>71</fpage>
          -
          <lpage>81</lpage>
          . doi:
          <volume>10</volume>
          .22630/RNR.
          <year>2018</year>
          .
          <volume>105</volume>
          .2.
          <fpage>17</fpage>
        </mixed-citation>
      </ref>
      <ref id="ref14">
        <mixed-citation>
          [14]
          <string-name>
            <surname>Kharchenko</surname>
            <given-names>V.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Kharchenko</surname>
            <given-names>G.</given-names>
          </string-name>
          (
          <year>2021</year>
          ).
          <article-title>Information provision for prospective development of agricultural enterprise</article-title>
          .
          <source>Economy and Society</source>
          , (
          <volume>23</volume>
          ). https://doi.org/10.32782/
          <fpage>2524</fpage>
          -
          <lpage>0072</lpage>
          /
          <fpage>2021</fpage>
          -23-20
        </mixed-citation>
      </ref>
      <ref id="ref15">
        <mixed-citation>
          [15]
          <string-name>
            <surname>Kluyver</surname>
            ,
            <given-names>T.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Ragan-Kelley</surname>
            ,
            <given-names>B.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Pérez</surname>
            ,
            <given-names>F.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Granger</surname>
            ,
            <given-names>B.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Bussonnier</surname>
            ,
            <given-names>M.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Frederic</surname>
            ,
            <given-names>J.</given-names>
          </string-name>
          , ... &amp;
          <string-name>
            <surname>Willing</surname>
            ,
            <given-names>C.</given-names>
          </string-name>
          (
          <year>2016</year>
          ).
          <article-title>Jupyter Notebooks-A publishing format for reproducible computational workflows</article-title>
          . In Positioning and Power in Academic Publishing: Players, Agents and Agendas (pp.
          <fpage>87</fpage>
          -
          <lpage>90</lpage>
          ). IOS Press.
        </mixed-citation>
      </ref>
      <ref id="ref16">
        <mixed-citation>
          [16]
          <string-name>
            <surname>Kostaridou</surname>
            ,
            <given-names>E.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Siatis</surname>
            ,
            <given-names>N.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Lampiris</surname>
            ,
            <given-names>G.</given-names>
          </string-name>
          , &amp;
          <string-name>
            <surname>Zafeiriou</surname>
            ,
            <given-names>E.</given-names>
          </string-name>
          (
          <year>2024</year>
          ).
          <article-title>Empirical Comparison of Facebook Prophet and Traditional Models for Tomato Price Forecasting in Greece</article-title>
          . Research on World Agricultural Economy,
          <volume>5</volume>
          (
          <issue>4</issue>
          ),
          <fpage>594</fpage>
          -
          <lpage>607</lpage>
          . https://doi.org/10.36956/rwae.v5i4.
          <fpage>1295</fpage>
        </mixed-citation>
      </ref>
      <ref id="ref17">
        <mixed-citation>
          [17]
          <string-name>
            <surname>Lim</surname>
            ,
            <given-names>B.</given-names>
          </string-name>
          ;
          <string-name>
            <surname>Zohren</surname>
            ,
            <given-names>S.</given-names>
          </string-name>
          <article-title>Time-series forecasting with deep learning: A survey</article-title>
          .
          <source>Philos. Trans. R. Soc. A</source>
          (
          <year>2021</year>
          ),
          <volume>379</volume>
          , 20200209. https://doi.org/10.1098/rsta.
          <year>2020</year>
          .0209
        </mixed-citation>
      </ref>
      <ref id="ref18">
        <mixed-citation>
          [18]
          <string-name>
            <surname>Mahanty</surname>
            ,
            <given-names>M.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Swathi</surname>
            ,
            <given-names>K.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Teja</surname>
            ,
            <given-names>K. S.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Kumar</surname>
            ,
            <given-names>P. H.</given-names>
          </string-name>
          , &amp;
          <string-name>
            <surname>Sravani</surname>
            ,
            <given-names>A.</given-names>
          </string-name>
          (
          <year>2021</year>
          ).
          <article-title>Forecasting the spread of COVID-19 pandemic with Prophet</article-title>
          .
          <source>Revue d'Intelligence Artificielle</source>
          ,
          <volume>35</volume>
          (
          <issue>2</issue>
          ),
          <fpage>115</fpage>
          -
          <lpage>122</lpage>
          . https://doi.org/10.18280/ria.350202
        </mixed-citation>
      </ref>
      <ref id="ref19">
        <mixed-citation>
          [19]
          <string-name>
            <given-names>Markets</given-names>
            <surname>Insider</surname>
          </string-name>
          . (n.d.).
          <source>Wheat Price Commodity [Data set]. Business Insider</source>
          . Retrieved from https://markets.businessinsider.com/commodities/wheat-price
        </mixed-citation>
      </ref>
    </ref-list>
  </back>
</article>