-Software systems are embedded into daily life and as such have significant effects on the behavior and decision making of both their users and the people affected by using these systems. Such effects can be positive or negative. Considering them in requirements engineering (RE) is an important step towards sustainable development, as RE strongly influences the development and the evolution of a software system. So far, RE researchers have focused on requirements about minimizing negative environmental effects. However, effects that are enabled by using a software system can also be positive. For example, a software system could motivate its users to take environment-friendly decisions. Corresponding requirements about such positive enabling effects have been far less addressed. In this paper, we present an exploratory case study where we elicited requirements about positive enabling effects with respect to environmental sustainability. The project we studied is about extending an existing decision support system for meal planning in canteens by game-based elements. The extended system shall motivate meal planners who work in canteens to make environment-friendly choices. Our contribution is an exemplar of concrete sustainability requirements as well as insight into the nature of sustainability requirements about positive effects that are enabled by the use of a software system. Index Terms-enabling effects; sustainability requirements; sustainable software systems; gamification; exploratory study;
Any software system and its utilization have effects causing
environmental impacts [
These are effects that are enabled by using a software system.
Enabling effects can be the result of automated processes
and/or of human behavior that is influenced by using the
software system. With regard to sustainable development,
enabling effects can be both positive and negative [
An e-commerce system providing business-to-consumer and
consumer-to-consumer sales services may influence human
behavior positively by encouraging people to sell used goods
so that they get re-used, but it can also lead to over-consumption,
which is negative. For a more detailed classification of effects
of software systems on sustainability see Berkhout & Hertin
[
Our dependency on software systems [
The importance of considering sustainable development in
software engineering has been emphasized by researchers
in the field [
Current RE contributions considering sustainable
development have focused on minimizing negative environmental
effects and referred to corresponding requirements as quality
requirements, e.g. [
Our goal is to better understand sustainability requirements related to positive effects, specifically the ones that are enabled by end-users while using a software system. This paper describes an exploratory case study in which we elicit and discuss such sustainability requirements for a decision support system (DSS) that is extended with game-based elements for motivating meal planners to make choices that reduce the CO2 value of their meals.
The contribution of our study is twofold. Firstly, we present an exemplar of concrete sustainability requirements related to positive enabling effects. Secondly, we discuss these sustainability requirements. The study reveals that when considering positive enabling effects (i) corresponding requirements include new requirements and existing requirements that become more important, and (ii) treating these requirements as quality requirements is inadequate as we found functional requirements and constraints. The study further provides some indication that (iii) corresponding requirements can be classified into requirements about integration, (meaningful) representation, and (fair) comparison, and that (iv) indirect stakeholders who Copyright c 2015 for this paper by its authors. Copying permitted for private and academic purposes. are no system users, but are affected by the use of the system and influence its success, are important.
This paper is outlined as follows. We first provide background on the case study and related work on RE with regard to sustainable development. In Sect. III we describe our research approach, the study design and the research questions. The results and threats to validity are presented in Sect. IV, followed by a discussion in Sect. V and conclusion and future work in Sect. VI.
as well as relevant background knowledge for readers less familiar with RE in the context of sustainable development. Further, we describe some earlier RE research which is relevant in the context of our study.
A. The Case Study emitted less CO2 than possible alternatives. To achieve this goal, the Compass Group (Switzerland) decided to order an extension of the existing DSS with game-based techniques for further processing the calculated LCA data and presenting them to the meal planners in a recurrent report.
3) The Context of our Case Study: The case study that we present in this paper contributes to the second part of the CarbonFoodPrint project. In the framework of a research collaboration with Eaternity and the Compass Group (Switzerland), the sustainability requirements for the new system were elicited and studied by the first author of this paper, together with a graduate student. As the focus on the CO2 emission caused by the production and transportation of ingredients was given, our study is confined to sustainability requirements with respect to CO2 which, actually, is only one aspect of sustainable development.
This case study is part of the project CarbonFoodPrint1 Software systems are embedded in their environment which
initiated by Eaternity2, a company that provides software- by nature is in a permanent process of change. As such,
supported solutions helping people to make their own eating developing and evolving a sustainable software system is an
habits climate-friendly. In this project Eaternity collaborates ongoing process. Typically, the decisions that shape a software
with the Swiss branch of the Compass Group 3, a world-leading system are taken during RE [
2) The Project Context: The overall goal of the CarbonFood- A sustainability requirement is a requirement for a
susPrint project is to motivate meal planners to select ingredients tainable software system which concerns sustainability.
whose production and transportation emitted less CO2 than A positive enabling effect is an effect that is enabled by
possible alternatives. The project consists of two parts. The first using a software system and positively contributes to the
part focuses on the calculation of CO2 emissions by applying transition towards sustainable development.
life-cycle assessment (LCA) [
Prior RE research has mainly conceptualized sustainability Research Questions. From this goal we derived two rerequirements as quality requirements (i.e., a sub-category of search questions: specific quality requirements in the taxonomy introduced by RQ1: What is specific about requirements concerning positive
Thereby, the focus was on goal modeling processes e.g. RQ2: How can game-based mechanics motivate positive
by regarding sustainability as a trade-off between business enabling effects when extending existing software systems?
goals [
We followed a “mixed methods” approach [
Most existing work on sustainability requirmements as 1) Study Setup: The process for all three steps and the
described above focus on direct effects (cf. the classification questions to be asked were elaborated by the first author of
presented in the introduction) and treat sustainability require- this paper with support from the graduate student, then reviewed
ments as goals or as specific quality requirements. Sustainability by a group of RE researchers and finally improved according
requirements related to enabling effects of a software system to the feedback received. The interviews and the questionnaire
are far less addressed both in research and – to our experience were both piloted with people neither specifically related to the
– also in industry. A possible explanation is that in most cases domain of RE nor to the one of sustainability. This approach
direct effects are directly connected to economic goals, whereas was chosen to make sure the questions are clear to participants
for enabling effects, such a relation is hard to establish in most who are unfamiliar with these domains [
Nevertheless, as outlined by Wang [
For choosing our research methodology, we considered the All steps of the study were conducted in German.
Consefollowing facts: (i) We wanted to analyze and better understand quently, the questions and interviewee quotes reported in this
sustainability requirements with respect to positive enabling paper are our translations of the German originals.
effects, (ii) there is little knowledge available about this kind 2) Selection of Participants: The Compass Group
(Switzerof requirements, (iii) we had the opportunity to study a real land) selected the participants for the contextual inquiry and
industrial project in this context. Given this situation, we chose the interviews. However, we could provide our criteria for the
an exploratory case study as our research methodology. Such a selection process. The following of our criteria were accepted
study enables an in-depth investigation of a phenomenon in its and applied by the company: (1) all participants are responsible
context [
According to our research plan and the given project context, Industry” (B&I) and “Eductation” (Edu)). We did not include we formulated our research goal as follows. gender, age or nationality into our selection criteria, since we
Goal. Analyze sustainability requirements for the purpose considered them as irrelevant for the purpose of the study. of developing sustainable software systems with respect to Eventually, 19 meal planners working in different canteens positive enabling effects from the viewpoint of the end-users participated in the semi-structured interviews.
The URL of the online questionnaire was sent to all student and then discussed between them in a retrospection meal planners (about 150). 67 participants finished the on- session. As mentioned above, the interview questions as well line questionnaire. However, seven of them did not answer as the interviews were piloted before conducting the actual the question about current reasons for changing ingredients. interviews.
The questionnaire results presented here come from the 60 5) Online Questionnaire: We used the results from the
meal planners who answered all questions (this includes all interviews as a basis for designing the online questionnaire.
participants of the interviews and the contextual inquiry). Our goal was to elicit quantitative information about important
3) Contextual Inquiry: To understand the current situation, aspects of sustainability requirements from a sample of involved
i.e., how meal planners currently work and apply the existing people which is larger than the number of meal planners
DSS, we conducted a contextual inquiry in two sessions: interviewed. We exploited the majority of the interview
the first one at the headquarters of the Compass Group questions in the online questionnaire, omitting the ones that
(Switzerland) and the second one in one of the canteens. focus on the end-user’s attitude towards the project. Table I
Contextual inquiry [
The interviews lasted between 25 and 45 minutes on average. inquiry session had primarily served for making the researchers
The time difference can be explained by our approach of familiar with the context of the project, so we excluded it from
conducting semi-structured interviews with a mix of open- the data set. Further, one interview was not recorded due to a
ended and specific questions. We did this for enabling the technical problem which we realized only after the interview
elicitation of both foreseen and unexpected information [
All interviews were conducted over Skype by calling the of 60 participants for analysis. With respect to the canteen interviewees on their business phones. This approach was sectors, i.e., Business & Industry (B&I) vs. Education (Edu), chosen because the interviewees were distributed over the the data are distributed as follows: (i) contextual inquiry session: whole country. So visiting them all would have been too costly zero B&I, one Edu; (ii) interviews: fourteen B&I, four Edu; and also not possible in the timeframe given for the interviews. (iii) online questionnaire: fifty B&I, ten Edu. Half of all interviews were conducted by the first author of D. Participant Demographics this paper, the other half by her graduate student. To align Some demographic information about the participants is the interview styles and reduce observer bias, the first two summarized in Table II. 83% of all participants work in interviews were conducted jointly by the first author and her
Identifier Original
Question Id1 IQ-1 2.d IQ-2 3.a IQ-3 IQ-4 QQ-1 QQ-2 QQ-3 QQ-4 4.a 6 4.1.1 5.3 7.1.1 6.1
Question (English translation) According to what criteria do you compose a meal? Can you imagine that the idea of reducing the CO2 value of meals due to the choice of ingredients is realizable in your canteen? Are you additionally to the CO2 value interested in the following information? i.What the CO2 value means e.g. how many kilometers driven by car do correspond to it? i.1 Are you further interested in other representations? If so in which? Do you believe that the CO2 values of different canteens can be compared with each other in such a report? What does motivate you to change a meal? Formulated in a clearer way, how strong does one of your changes affecting a meal component or ingredient depend on the following criteria? (costs, variety, customer preference, season, compliance, environmental aspects) How should the CO2 emission value of your meals additionally be represented in order to raise your interest? (number of kilometers a mean of transportation has to make; amount of energy an ordinary private household has to use; number of days an ordinary private household has to be heated in order to emit the same amount of CO2; number of trees that are needed to compensate the same amount of CO2); How good do you think is the following information? Segmentation of the CO2 based on the process steps; meal components; origin of ingredients How strong have the following factors to be considered in order you perceive the comparison of the CO2 emission of different canteens to be fair? (size of the canteen according to the number of cooked meals; the number of employees working in the kitchen; the number of meal categories served in a canteen; the customer preferences) “IQ” refers to the interview questions and “QQ” to the questionnaire questions. The column “Original Question Id” refers to the corresponding original question id of the interview or the questionnaire, available under 1: http://www.ifi.uzh.ch/rerg/research/stakeholderengagement/garuso B&I canteens and 17% in Edu canteens. On average, the participants have more than five years experience in their position. Regarding meal variety and number, participants working in B&I canteens have three meal categories on average (e.g., meal with meat, vegetarian, low-carb), while participants working in Edu canteens have four. Around 40% of all participants from both sectors work in canteens that produce between 150 and 499 meals per day. 42% of the B&I canteens and 20% of the Edu canteens produce less than 150 meals per day, and more than 500 meals are daily produced in 16% of the B&I canteens and in 40% of the Edu canteens.
All data is exploratory, which means we did not pre-specify
a hypothesis as it is done in a confirmatory analysis. The
end-product of exploratory data analysis is rather suggesting
patterns for further studies and providing hypothetical insight
into these patterns instead of statistical figures [
1) Contextual Inquiry: Information from the contextual inquiry sessions was first structured to identify main work processes which then were used for defining the interview questions. In the presentation of the results in the next section, the data from the contextual inquiry is not analyzed separately, but presented together with the data from the interviews.
2) Semi-Structured Interviews: To be able to better evaluate
the data from the interviews we structured the data by first
transcribing and then coding them according to the process
described by Seaman [
3) Online Questionnaire: As it is common in exploratory studies, we visually analyzed the quantitative data from the questionnaires, choosing divergent stacked bar charts.
presenting qualitative results, the data are complemented with quotations from the interviewees. The quotations are written in italic, the interviewee who stated the quote is indicated in brackets by “I-” followed by the number of the interview. We coded relevant information in the qualitative results to structure and quantify them; these codes are underlined and in brackets. Table III lists the sixteen codes that we used, together with the frequency of their appearance in the interviews. The questionnaire results for QQ-1–QQ-4 (cf. Table I) are visualized in Figures 1-4 in the same order as the corresponding questions.
We present the results grouped by topics. Within each topic, we first present the results from the interviews regarding this topic, and then the corresponding results from the online questionnaire.
The first aspect we investigated was whether and how the current set of requirements changes from the end-users’ perspective when adding the dimension of sustainable development to the domain context (RQ1). We first focused on actually existing requirements causing the participants to change ingredients in their current work process. Second, we elicited requirements that the participants perceive as important if they had to select ingredients with respect to CO2 emission. This subsection highlights the aggregated results related to this aspect.
ically asked the interviewees about reasons for changing ingredients in the proposed meals they get from the culinary development team (IQ-1). The three criteria mostly mentioned are customers’ preferences, costs and variety.
As indicated in Table III for thirteen interviewees customers’ preferences (changeIngredients_customers_current) are a strong reason to change ingredients, twelve emphasized the relevance of cost restrictions (changeIngredients_costs_current) and six mentioned the variety (changeIngredients_variety_current) of their meals as an important reason. Interviewee I-8, for example, highlighted both variety and customers’ preferences: “I do it according to the following criteria, such that there is variety. Theoretically, pork is the cheapest meat we can get, but I nevertheless look that it is only served once a week. Also a little bit because of our Muslims (...)”.
In the online questionnaire, we further explored these results by asking the participants to rate the importance of costs, variety, customers’ preferences, together with the seasons, compliance with suppliers, and the environment as a reason for them to change the ingredients (QQ-1). Participants could rate the importance on a semantic differential scale of four criteria: “Plays no role at all”, “Plays a minor role”, “Certainly plays a role”, “This criterion is one of the most important reasons for change”. The results shown in Fig. 1 support what we found in the interviews: Customers’ preferences and costs are the two most important reasons to change ingredients in both Edu and B&I canteens. Variety and season come next. Participants working in Edu canteens rate these two criteria as equally important, while participants working in B&I canteens rate season to be slightly more important than variety.
2) Considering Sustainability Requirements: When asked the interviewees whether they can imagine reducing the CO2 emission of their meals by selecting specific ingredients (IQ2), thirteen were positive about having the potential to do so (successCO2Red_changingIngredients_new). However, the interviewees agreed that this goal is only achievable when considering certain constraints. The results described below show that (i) costs and customers’ preferences are perceived as the two most relevant constraints if the context of sustainable development is added; (ii) the influence of these two constraints becomes stronger in this context and new constraints become relevant; (iii) an integration of the game-based extension into the existing DSS is important.
by nine interviewees to challenge the successful consideration of CO2 emission when selecting ingredients. Three of them regard cost restrictions as a major criteria for a project failure. The rest of them is not that strict, however they mentioned that local and organic products usually are more expensive than non-organic products or products from farther away. They highlighted that if their budget remains the same, customers had to pay the cost difference. Interviewee I-17 considered the relevance of a company-wide change: “Well it [the success] depends on what kind of food it is. In my opinion, if costs raise, we have to pass these costs on to our customers in order to stay in the green zone [with the costs]. (...) Actually, the whole company should have to participate.”. I-14 stated: “(...)
Customers’ preferences are further regarded as a constraint that challenges the success of the project (constraintCO2Red_customers_new) by nine interviewees. Seven of them can imagine to possibly manage this challenge by involving the customers (e.g., by explaining the effects). The other two do not think that customers will change their eating habits or pay more for climate-friendly food. I-14 stated for example: “Well, the cooks would like to consider this [the CO2 emission related to the ingredients]. It has been a nonsense to offer tomatoes in December. However, it is a fact that not us, but the customers do rule the market (...) In my opinion the % of respondents 100 80 60 40 20 0 20 40 60 80 100
Plays no role at all Plays a minor role Certainly plays a role This criterium is one of the most important reasons for change sn #trees for compensation du tee #heating days in a household -E an#kilometers by any mean of transportation
C Eletricity used in a private household
#trees for compensation issseun tseeann#kilometers by any mean of transportation
#heating days in a household -B C Eletricity used in a private household
This makes absolutely no sense I regard this as rather meaningful % of respondents 100 80 60 40 20 0 20 40 60 80 100 This seams not very meaningful I cannot answer this question Absolutely, this is absolutely meaningful awareness of the customers is not yet there.”
The size of the work space was highlighted by two interviewees (constraintCO2Red_space_new) as a major constraint. Little space in the kitchen affects work processes and as such the choice of ingredients. I-12 put it this way: “Our restaurants are not all equipped in the same way (...) Some [of us] really must additionally plan their meals based on the available space [to process the food] and the storage possibilities and then decide whether they buy fresh broccoli or frozen broccoli.”
The proper integration (successCO2Red_integratedInWorkProcess_new) of the game-based extension in the existing DSS is regarded as highly important by thirteen interviewees. For example, six of them said that it is highly important to have immediate access to alternative ingredients with a lower CO2 emission value while planning meals over the system (successCO2Red_alternativesShown_new). I-2 emphasized: “(...) there really must be alternatives with which the CO2 emission value can be reduced. Showing a direct alternative in the sense of ‘tomatoes from Italy instead of cherry tomatoes from overseas’ should be possible.” In this context, I-7 highlighted time pressure as a reason: "When we get the [suggested] meal plan, it [the system] has to be ready with the CO2 emission values. Because we cannot search extensively for this information on the lists of the vegetable, meat, or fish suppliers (...) this [information] has to be integrated and then we can work.”
The second aspect we investigated was about how gamebased mechanics have to be applied to motivate positive enabling effects in the given context (RQ2). Our focus was on a meaningful representation of the CO2 emission value and on relevant factors for comparing the values of different canteens with each other. In this sub-section we present the aggregated results.
We asked the interviewees if the CO2 emission shall be represented (successCO2Red_CO2Rep_new) by more familiar measures (IQ-3) and provided the number of kilometers driven (i.e., how many kilometers one could drive for emitting the same amount of CO2) as an example. Seventeen interviewees agreed on the importance of a meaningful representation. I-12 added that such a value would even be more meaningful if represented by a journey. “It would be good if you could say, we have saved that amount of CO2, this is enough to travel from here to
(...) because we do not know what consumes how much [CO2].
we don’t know what is a good value and what is a bad one.” Five interviewees highlighted the relevance of using graphics and pictures (successCO2Red_CO2RepGraphically_new). I-14 explained it this way, “(...) something like ’[with this amount of CO2] you could have driven from here to there with a truck’ and then showing something similar to Google maps. This way, it becomes visible right away that I could have driven to
The questionnaire results underline these results. Together with the given example on the amount of kilometers we provided three more representation options to rate for (QQ-2): the number of trees needed to compensate the amount of CO2 emitted, the used heating energy, and the used electricity in an average household (Fig. 2). These four options could be rated on a semantic differential scale of 5 criteria: “This makes absolutely no sense”, “This seams not very meaningful”, “I can’t answer this question”, “I regard this as rather meaningful”, and “Absolutely, I think this is absolutely meaningful”. The results show that the number of trees needed for compensation and the number of kilometers that can be driven are similarly perceived as highly meaningful for representing the amount of CO2 emissions. Participants from both sectors were much less interested in a representation by the energy consumption in a household of both electricity and heating.
Segmentation of the CO2 value was raised by four interviewees. Two of them wanted a segmentation based on the origin of ingredients (successCO2Red_CO2PerOrigin_new) e.g., the CO2 value of a tomato from Greece compared to one from Italy. Three interviewees were interested in segmenting the CO2 value according to the two process steps of production and transportation (successCO2Red_CO2PerProcessSteps_new), and all four found it relevant to segment the meals with regard to their components (successCO2Red_CO2PerComponents_new), e.g., the two components pasta and pasta sauce. I-14 made this very clear: “When you do something like this [the project as a whole], I think it is good that we have a learning effect, something like ’Ahaaaaaa, there it is, this shrimp has messed up our whole meal statistics (...) This way rethinking happens.
These results were exploited further in the questionnaire by asking to rate the segmentation factors origin, meal components, s n du tee and process steps (QQ-3) on a semantic differential scale of four criteria: “I don’t like this at all”, “I think this is rather bad”, “I think this is rather good”, “Absolutely, I think this is awesome”. The results show that the majority of both sectors is interested in comparing ingredients based on their origin (Fig. 3).
As game-based techniques typically involve comparisons, we specifically asked whether the CO2 value of different canteens can be compared with each other (IQ-4); thirteen interviewees said yes (comparisonCO2Possible_gamification_new). Eight of them stated that the most important condition to consider for enabling comparisons between canteens is the number of meals produced (comparisonCO2Possible_numberOfMeals_new).
with a large one (...) If I compare two small canteens with each other that sell on average approximately sixty to eighty meals per day, then I think this is comparable. (...) I think here we should differentiate such that we only compare very similar canteens, also with respect to the location.”
These interview results are supported by the results from the questionnaire (Fig. 4). The participants could rate the importance of number of meals, of employees working in the kitchen, of meal categories offered, location of the canteen, customers’ preferences for comparison (QQ-4), on a semantic differential scale of four with the two opposite criteria: “Plays no role at all” and “Plays a significant role”. The majority of participants from B&I canteens selected the number of meals, followed by customers’ preferences to enable fair comparison, while the majority of participants form Edu canteens selected customers’ preference as the top criterion, followed by the number of meals.
We discuss the threats to validity using the usual four
categories: internal, external, construct, and conclusion validity
[
Internal Validity reflects the relationship between cause and effect. The internal validity of our study is limited due to its very nature: in an exploratory case study in a real world project, many potentially confounding factors cannot be controlled. A potential threat is the fact that the persons participating in the contextual inquiry as well as the interviewees were selected by the Compass Group (Switzerland). We do not consider this a major threat because we provided the company with our selection criteria and also did not find any evidence for selection bias when analyzing the interviews. Answering the online questionnaire was voluntary, which may cause the results to be biased due to highly supportive or highly nonsupportive participants. Since the subject of the study was equally interesting for both supporters and opponents, we do not believe that the outcome of our study is affected by this potential threat. We mitigated potential maturation problems by scheduling the interviews during working hours and limiting their duration to 20-40 minutes.
External Validity refers to the extent of being able to generalize the results. The biggest limitation to the external validity of our study is the fact that (i) the study was conducted in a single company and (ii) the project was limited to positive enabling effects with respect to CO2 emission. However, the setting of our study is typical for systems in the service domain: employees of a service company use a software-based system as end-users to provide services to the customers of the company, while the customers’ preferences as well as cost considerations have a major influence on the system’s requirements. Further, reducing CO2 emission is a problem that, in our opinion, can be considered to be representative for the whole domain of problems considering sustainable development. Based on these two reasons, we argue that our results are generalizable at least to some extent to positive enabling effects about sustainability in general for systems in the service domain.
Construct Validity describes our ability to measure what we actually intend to measure. All participants had the same tasks. However, we believe to have reduced monooperation bias by including different work locations and work domains (Business & Industry, Education) into our study. We have minimized mono-method bias by using methodological triangulation (contextual inquiry, interview, questionnaire). To avoid evaluation stress, we assured all participants that their data were treated confidentially and evaluated for research purposes only.
Conclusion Validity is concerned with drawing correct conclusions based on our observations. The first author was involved in designing the study and executing the elicitation techniques, which could potentially cause observer bias. For mitigating this threat, we used methodological and observer triangulation and reviewed the structure and questions of all three elicitation methods with a group of experienced RE researchers. By conducting several pilot studies we strengthened the quality of our wording. Further, we encouraged the interviewees to ask for clarification if something was unclear. Therefore, we do not consider measure reliability as a major threat.
The results of our study show that the requirements do change when sustainability comes into play. In our study, when extending the existing DSS for meal planning with gamebased mechanics for motivating environment-friendly choices to achieve a reduction of CO2 emissions, we mainly found three kinds of changes in requirements: new constraints, existing constraints that become more important, and new functional requirements.
For example, the size of the kitchen is a new constraint that the interviewees only perceive when the system is used in the context of positive enabling effects for achieving a reduction of CO2 emission. The smaller the kitchen, the less fresh food can be processed, which means that the meal planners have to go for more frozen or pre-processed food. This, in turn, has an effect on the CO2 footprint of the meals.
Participants from both Edu and B&I canteens identified customer preferences and cost restrictions as the most important constraints. The interviewees emphasized their fear about increased cost constraints in the context of positive enabling effects due to higher prices for local and organic food. Further, they are afraid of loosing customers by excluding off-season products, which results in a smaller variety of food. That means that the existing constraints of customer preferences and cost restrictions become more important in a sustainability context.
72 percent of all interviewees emphasize the need to integrate the information about CO2 emission values into the DSS. 33 percent specifically want to be able to immediately access a list of alternative ingredients with respect to their CO2 footprint. These are new functional requirements.
Consequently, treating sustainability requirements as a subcategory of specific quality requirements (cf. Section II-B2) turns out to be inadequate. Requirements concerning positive enabling effects can be functional requirements or constraints.
The growing importance of customer issues in the context of positive enabling effects such as customer preferences and cost restrictions also provides evidence that in the context of sustainability requirements, there is a strong need for taking into account also the indirect stakeholders of a system (i.e., those who are not end-users of the system, but are affected by its use, e.g., customers).
based mechanics directly into the underlying system and that end-users have to perceive the representations of sustainability goals to be meaningful as well as comparisons to be fair.
As mentioned above, the interviewees emphasize the need to integrate the information about CO2 emission values into the DSS and want to be able to immediately access a list of alternative ingredients with respect to their CO2 footprint.
The requirement of representing the CO2 values in a meaningful way is perceived as relevant by 94% of all interviewees. Metaphorical representations such as number of trees needed to compensate the CO2 emission or number of kilometers made by a mean of transportation until the same amount of CO2 is emitted are preferred over more abstract representations such as energy equivalents. Interviewees also mentioned the importance of concrete and visual representations e.g a concrete example for a trip from city A to city B, preferably indicated on a map. A proper segmentation of the displayed information is also important. In our study, most participants favored the origin of ingredients as segmentation criterion.
As discussed in our previous research [
When analyzing the interview data with respect to the codes that originate from information provided spontaneously by the interviewees (see Table III), we found that this information (and hence, the corresponding sustainability requirements) can be grouped into three categories: (a) integration of sustainability information into the current system and work process ( i.e., by properly extending the current software system instead of just adding a new, separate module), (b) meaningful representation of the addressed sustainability aspect (CO2 emission in our study), and (c) fair comparison of the achievements of the addressed users (meal planners in different canteens in our study). Although more research is necessary to establish the generalizability of this finding, our study provides some evidence that a classification of sustainability requirements with respect to positive enabling effects into the classes integration, (meaningful) representation and (fair) comparison makes sense.
Requirements for a software system do change when sustainable development is considered.
We find both new requirements and existing requirements that become more important.
Considering sustainability requirements to be a subset of quality requirements is inadequate. We also found functional requirements and constraints.
evidence, but further research is necessary.
classes: integration, (meaningful) representation and (fair) comparison.
Indirect stakeholders, i.e., those affected by the use of the deployed system, should be involved when eliciting sustainability requirements.
We reported on the results of elicited sustainability requirements regarding positive enabling effects. The study includes 78 data points from 60 participants working in 60 different canteens. Our main contribution is to reveal differences of such sustainability requirements compared to requirements in traditional settings, as well as important requirements to consider in a context of sustainability requirements for favorable enabling effects. Moreover, we found evidence that indirect stakeholders are important in this context and a possible classification of sustainability requirements.
In our future work we will further exploit the findings of this study. In particular, we plan to investigate the elicitation of sustainability requirements from indirect stakeholders who are outside of organizational reach.
duct this study and all employees of the Compass Group (Switzerland) who participated in the study. This research was partially funded by Gebert Rüf Stiftung under grant number GRS-023/13.