=Paper=
{{Paper
|id=Vol-1684/paper15
|storemode=property
|title=Measuring Complexity of SAP Systems
|pdfUrl=https://ceur-ws.org/Vol-1684/paper15.pdf
|volume=Vol-1684
|authors=Ilja Holub,Tomas Bruckner
|dblpUrl=https://dblp.org/rec/conf/bir/HolubB16
}}
==Measuring Complexity of SAP Systems==
https://ceur-ws.org/Vol-1684/paper15.pdf
Measuring complexity of SAP systems
IljaHolub and Tomas Bruckner
University of Economics, Prague
{ilja.holub,tomas.bruckner}@vse.cz
Abstract.The paper discusses the reasons of complexity rise in ERP system
SAP R/3 and proposes a method for measuring complexity of SAP. A program
in ABAP for measuring complexity of particular SAP implementation is pro-
posed as a tool for keeping ERP complexity under control. Main principle of
the measurement method is counting the number of items or relations in the sys-
tem. The program is based on counting of records in organization tables in SAP.
Keywords:Complexity, ERP, SAP, measurement, information system, busi-
ness.
1 Introduction
In this paper we state the related approaches to complexity and show that several
methodologies used for ICT and information systems management don’t handle the
topic of complexity well. Then we discuss the complexity of SAP ERP system and the
reasons for rising complexity in SAP implementations. Then we propose a method
and a program for measuring complexity of ERP systems and describe a verification
of the methodon a certain business case.
2 Related work on measuring complexity
A good theoretical basis for describing and exploring complexity can be found in the
mathematical graph theory[1][2], which can be applied to some IS/ICT models to
facilitate their quantification and subsequent comparison and, in some cases, even
their simplification. Publications that come closest to the topic of business infor-
mation system complexity deal with using metrics to measure complexity, such as
information flow metrics, [3] Halstead’s method or functional point analysis [4], or a
simple number of source code lines [5]. There are also publications dealing with the
impacts of complexity on system security and maintainability. Their objective is to
adapt the MATra framework to describe certain aspects of complexity [6] and/or to
point out the negative impacts of complexity on the business [5].
The topic of managing information system complexity is discussed, for example,
by John Maeda in his book ‘The Law of Simplicity’, where he defines ten rules of
simplicity. [7] ERP systems are specifically discussed in ‘A Metric for ERP Complex-
ity’ [3], which counts process inputs and outputs and works with the concepts of in-
ternal and external module complexity, applying data flow complexity according to
[8]. Best practices for simplicity of IS describes the book „Managing Complexity of
Information Systems“[9].
The proposed SAP measurement method is a part of a general complexity man-
agement methodology being prepared by authors.
The important principle is to keep the managing complexity itself simple. The
managing complexity including measurement should not bring another complexity, so
it should be kept simple and simplified even at the expense of accuracy or precision.
The reason for measuring complexity is to have a metric, which can measure not the
actual absolute complexity of the system, but relative complexity in time or before
and after a change, and which is therefore useful for managing complexity and keep-
ing the system as simple as suitable.
When measuring system complexity, the first step is to select relevant content di-
mensions D and the IS lifecycle phase f, using which we wish to measure complexity.
Let us designate their number as d. For dimension iin phase f we can define complexi-
ty Cf(Di) as the number of entities (elements and/or links) of its model.
Let us define system complexity C(S) as a sum of the complexities of each of its
dimensions C(Di). Thus, complexity C of system S in phase f is the number of entities
(elements and/or links) in the models of each of its content dimensions (D) selected in
the given phase; d shall be the total number of dimensions considered.
d
C f ( S ) C f ( Di ) , (1)
i 1
This formula (1) allows us to quantify the complexity of a system or its part, and in
practice it can be used to compare various systems or solution alternatives that meet
the given requirements, yet there is no objective criterion why one of them should be
selected.
3 Complexity of SAP
In this paperwe research the SAP ERP information system in terms of complexity and
use it as an example of how the complexity of an information system can be defined
and calculated, what its causes are, and what impact system complexity has. We dis-
cuss the context of SAP complexity and propose simple way to measure it. Resulted
measure is meant to be used to control unexpected complexity grow during several
phases of information system lifecycle.
3.1 SAP systems and the growth of their complexity
The complexity of the SAP system is determined in part by the selection of the set of
business processes that are to be supported by the system and also by which systems
or modules are to be implemented and how.
3.2 Measuring the complexity of SAP systems
The complexity of SAP system changes over its lifecycle and if it is not specifically
managed, it grows. To calculate it we use a program written in the ABAP program-
ming language.
Which parameters influence the complexity of SAP systems? The complexity of
the system grows during its customisation. The SAP system contains tens of thou-
sands of customisation tables, the entries of which define the system's settings and
determine its complexity. The basic setting that determines all the others is the com-
pany's organisational structure setting. Like all others it takes place in an SPRO trans-
action1.
Program for complexity calculation.In order to calculate complexity, the authors
created the program IHC_ORG (Identify High Complexity), which counts the entries
in the relevant tables (here the tables that determine the settings for the enterprise
structure) and at the same time aggregates them according to individual SAP modules.
The result of the program is a single number which counts items in selected tables, or
possibly set of numbers sorted by SAP modules to which the tables primarily belong.
The program can be launched for one or multiple clients of the given system and then
their complexity can be compared.
Evaluation. The method, the program and its usage was evaluated in a case study of
division of one industrial company in Germany (Company A), which was divided to
two companies (Companies B and C), of which one (C) was merged with other one
company (D). The result is described in a study (not yet published, in review process).
The resulted measure was used to manage and decrease resulted organisation structure
complexity of ERP re-implementation. The Fig. 1 shows the result of measuring
complexity of SAP systems of companies C and D.
1800
1600
1400
1200
1000
800
600
400
200
0
Starting Complexity of C Expected of C + D Resulting of C + D Increase by D
Fig. 1.Organization structure complexity of the SAP system in Enterprises C and D
1SPRO – a four or more digit code used when working in SAP by which the user directly
launches the given transaction (application) without having to click through what are often
several levels of menus.
4 Conclusion
We discussed the context of complexity in SAP systems, proposed a method for
measuring complexity of running SAP R/3 ERP systems, and implemented the meth-
od in a software. The complexity of SAP systems is influenced by extension of SAP
R/3 system by other systems and by duplication functionality and data structures out-
side the core ERP system. The simple measurement method can count selected items
in the system from a chosen dimension, which brings a tool for observing complexity
in time and during changes and for reducing complexity and keeping the system as
simple as possible.
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