The purpose of this paper is to provide a practical approach for prioritizing the most practiced Critical Success Factors (CSFs) for six sigma implementation. The most commonly accepted CSFs for six sigma were identified from the literature. Then, the interactions among twelve CSFs have been studied using one of the mathematical/soft-operational research tools, that is, the Interpretative Structural Modeling (ISM). The developed model was illustrated using a case study selected from an automotive service industry. The findings implied that almost all of the CSFs are classified as linkage variables. The developed model provides a road map that assists practitioners to understand the process through which six sigma is practiced in a certain enterprise. Although the studied case was selected from the automotive service industry, the outcome of the proposed ISM model supported the results of the previous empirical studies in a sense that all factors for six sigma implementation were in fact critical (i.e. none of them was located within the autonomous category).
Without doubt, there is no one single way for six sigma implementation, and consequently, six sigma can be conceptually defined in different ways. Indeed, due to the fact that the concept of six sigma covers a wide range of problem solving tools that aim to change the culture in an optimal manner, it is quite difficult to have a straightforward definition for it [
The concept of six sigma was introduced firstly by Motorola in the early 1980s [
・ Linking the achievement to financial measures such as Return on investment (ROI).
・ Incorporating the soft elements of system improvement (such as culture, cooperation and all other elements related directly to human’s behavior) with all aspects of process management (the hard elements).
・ Combining the statistical (or any quantitative) methods and other (soft) techniques in a chronological way under the umbrella of the five famous steps of implementing six sigma (Define―Measure―Analyze―Im- prove―Control).
・ Creation of solid base of teamwork infrastructure through identifying different scopes and hierarchal levels for six sigma project management (Yellow Belts, Green Belts, Black Belts,… etc.).
Therefore, it is not surprising that researchers as well as practitioners are in agreement regarding six sigma’s benefits. However, the issue of developing a generic framework for six sigma implementation has always been investigated in the literature [
This paper argues that a further investigation should be conducted through developing an Interpretive Structural Modeling (ISM) to understand the relationships among these factors. Put simply, the aim of this paper is to provide a practical approach to prioritize the most practiced Critical Success Factors (CSFs) of implementing six sigma. The most commonly accepted CSFs of six sigma implementation are identified from the literature. Then, the interactions among twelve CSFs have been studied using the methodology of ISM. The developed model is illustrated using a case study selected from an automotive service industry.
The CRFs represent the factors that are considered “critical” to the success of any firm and, consequently, failing in attaining the relevant goals of these factors implies disaster failing of the entire firm [
・ Upper management support and involvement.
・ Organizational infrastructure.
・ Training.
・ Tools.
・ Links to human resources-based actions.
Afterward, Antony and Banuelas [
・ Management involvement and commitment.
・ Understanding tools and methods for six sigma.
・ Linking six sigma to business strategy.
・ Linking six sigma to customer.
・ Project selection and tracking.
・ Organizational infrastructure.
・ Cultural change.
・ Project management skills.
・ Linking six sigma to suppliers.
・ Training.
・ Linking six sigma to human resources.
The factor of “Communication” has also been considered by Coronado and Anthony [
・ Initiating process management.
・ Determining performance through reporting.
・ Integrating supports for projects by determining the needed updates during staff meetings.
After that, Johnson and Swisher [
・ Continued and noticeable managerial commitment.
・ Ongoing education and training for executives and team members.
・ Outlining clear expectations and electing project leaders carefully for leadership capabilities.
・ Careful selection of significant projects that have strategic potential.
About eight years ago, Kwak and Anbari [
・ Managerial commitment and involvement.
・ Skills for managing and selecting projects.
・ Motivation for cultural change.
・ Training and ongoing education for six sigma.
Recently, Brun [
CSFs for six sigma | Acronym |
---|---|
Management involvement and commitment | CSF1 |
Cultural change | CSF2 |
Communication | CSF3 |
Organizational infrastructure and culture | CSF4 |
Education and training | CSF5 |
Linking six sigma to business strategy | CSF6 |
Linking six sigma to customer | CSF7 |
Linking six sigma to human resources | CSF8 |
Linking six sigma to suppliers | CSF9 |
Understanding tools and techniques within six sigma | CSF10 |
Project management skills | CSF11 |
Project prioritization and selection | CSF12 |
ISM is a well-known approach that facilitates visualizing complex relationships among set of factors in order to enable the decision maker to understand the complex situation [
Within the field of quality management, Mehta, Verma, and Seth used the Delphi method to identify the principles of TQM in engineering education [
Critical success factors assure successful installation, functioning and sustainability of six sigma system; whereas, enablers assure successful installation of a six sigma system. Therefore, enablers are defined as a subset of critical success factors…there is a very thin line between the general term success factors and specific term enablers, but these are defiantly different in definition and application.
Such a difference encouraged the author to apply the method of ISM in order to investigate the CSFs of six sigma within the automotive service industry, in Saudi Arabia, as illustrated in this paper.
According to the previous applications of ISM [
1) Defining a list of elements or factors that are going to be investigated. These factors can be identified through surveys, experts opinions, or reviewed literature (i.e. as shown in this paper).
2) Setting up contextual relationships among the defined factors.
3) Developing a Structural Self-interaction Matrix (SSIM) as a reflection of the pair-wise contextual relationships between the factors.
4) Forming the reachibility matrix from the developed SSIM. Then, the reachability matrix is checked for transitivity. Transitivity of the contextual relation within ISM implies respecting the assumption that if factor A leads to factor B, and factor B leads to factor C, then consequently, factor A leads to factor C.
5) Dividing the developed reachability matrix into different levels.
6) Drawing a directed graph (diagraph) according to the rechability matrix.
7) Converting the developed diagraph into an ISM-based model by replacing nodes numbers with factors names. Note that this step can be avoided if factors names are used directly/initially.
8) Reviewing the model for further modifications or clarifications.
As discussed above, the literature of the CSFs for six sigma implementation is critically reviewed to obtain the most commonly accepted CSFs, with respect to the recent update in the literature. Accordingly, a list of twelve CRFs for six sigma has been identified as shown in
・ V: if CSF i leads to successful implementation of CSF j.
・ A: if CSF j leads to successful implementation of CSF i.
CSFs | CSF12 | CSF11 | CSF10 | CSF9 | CSF8 | CSF7 | CSF6 | CSF5 | CSF4 | CSF3 | CSF2 |
---|---|---|---|---|---|---|---|---|---|---|---|
CSF1 | V | O | O | X | V | X | V | X | V | X | V |
CSF2 | A | O | A | A | A | A | A | A | O | X | |
CSF3 | X | A | A | X | X | X | V | A | V | ||
CSF4 | A | O | O | A | A | A | A | O | |||
CSF5 | O | V | V | A | A | A | A | ||||
CSF6 | X | V | V | X | X | X | |||||
CSF7 | X | V | V | X | X | ||||||
CSF8 | A | V | X | X | |||||||
CSF9 | X | V | X | ||||||||
CSF10 | V | V | |||||||||
CSF11 | O | ||||||||||
CSF12 |
・ X: if both, CSF i and CSF j, leads to successful implementation of each other.
・ O: if there is no relation between CSF i and CSF j.
The next step is to convert the SSIM into a binary matrix, known as the initial reachability matrix as shown in
・ If the (i, j) input in the SSIM is V, the (i, j) input in the reachability matrix becomes 1 and the (j, i) input becomes 0.
・ If the (i, j) input in the SSIM is A, the (i, j) input in the reachability matrix becomes 0 and the (j, i) input becomes 1.
・ If the (i, j) input in the SSIM is X, the (i, j) input in the reachability matrix becomes 1 and the (j, i) input also becomes 1.
If the (i, j) input in the SSIM is O, the (i, j) input in the reachability matrix becomes 0 and the (j, i) input also becomes 0.
Then, the process of transitivity check is executed through considering the assumption that if CSF1 leads to successful implementation of CSF2, and CSF2 leads to successful implementation of CSF3, then CSF1 leads to successful implementation of CSF3. Consequently, some inputs in the initial reachability matrix are converted from 0 to 1 in the final reachability matrix. The converted inputs are labled by “*” as shown in the final reachability matrix (
The next step is to classify the CSFs in different levels. In this step, three terms should be clearly explained: reachability set, antecedent set, and intersection. As shown in
The antecedent set is the reversal of the reachability set in a sense that antecedent set includes all CSFs that have a direct or indirect influence on a certain CSF (i), including CSF (i) itself. For instance, as CSF4 is influenced by all CSFs, all twelve CSFs are considered within the antecedent set for CSF4. It can also be seen that all input entries for the column corresponding to CSF4 in
It is important to note that the column of intersection for each CSF (i) contains any CSF that is existing in both the reachability set and the antecedent set the reachability set and the antecedent set. To illustrate, for CSF4, only (4) is considered in both columns (the reachability set and the antecedent set) and, consequently, the col-
CSFs | CSF1 | CSF2 | CSF3 | CSF4 | CSF5 | CSF6 | CSF7 | CSF8 | CSF9 | CSF10 | CSF11 | CSF12 |
---|---|---|---|---|---|---|---|---|---|---|---|---|
CSF1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 0 | 0 | 1 |
CSF2 | 0 | 1 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
CSF3 | 1 | 1 | 1 | 1 | 0 | 1 | 1 | 1 | 1 | 0 | 0 | 1 |
CSF4 | 0 | 0 | 0 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
CSF5 | 1 | 1 | 1 | 0 | 1 | 0 | 0 | 0 | 0 | 1 | 1 | 0 |
CSF6 | 0 | 1 | 0 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 |
CSF7 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 |
CSF8 | 0 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 0 |
CSF9 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 |
CSF10 | 0 | 1 | 1 | 0 | 0 | 0 | 0 | 1 | 1 | 1 | 1 | 1 |
CSF11 | 0 | 0 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 0 |
CSF12 | 0 | 1 | 1 | 1 | 0 | 1 | 1 | 1 | 1 | 0 | 0 | 1 |
CSFs | CSF1 | CSF2 | CSF3 | CSF4 | CSF5 | CSF6 | CSF7 | CSF8 | CSF9 | CSF10 | CSF11 | CSF12 | Driving power |
---|---|---|---|---|---|---|---|---|---|---|---|---|---|
CSF1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1* | 1* | 1 | 12 |
CSF2 | 1* | 1 | 1 | 1* | 0 | 1* | 1* | 1* | 1* | 0 | 0 | 1* | 9 |
CSF3 | 1 | 1 | 1 | 1 | 1* | 1 | 1 | 1 | 1 | 1* | 1* | 1 | 12 |
CSF4 | 0 | 0 | 0 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 |
CSF5 | 1 | 1 | 1 | 1* | 1 | 1* | 1* | 1* | 1* | 1 | 1 | 1* | 12 |
CSF6 | 1* | 1 | 1* | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 12 |
CSF7 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 12 |
CSF8 | 1* | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1* | 12 |
CSF9 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 12 |
CSF10 | 1* | 1 | 1 | 1* | 1* | 1* | 1* | 1 | 1 | 1 | 1 | 1 | 12 |
CSF11 | 1* | 1* | 1 | 1* | 0 | 1* | 1* | 1* | 1* | 0 | 1 | 1* | 10 |
CSF12 | 1* | 1 | 1 | 1 | 1* | 1 | 1 | 1 | 1 | 1* | 1* | 1 | 12 |
Dependence power | 11 | 11 | 11 | 12 | 9 | 11 | 11 | 11 | 11 | 9 | 10 | 11 |
CSFs | Reachability set | Antecedent set | Intersection | Level |
---|---|---|---|---|
CSF1 | 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12 | 1, 2, 3, 5, 6, 7, 8, 9, 10, 11, 12 | 1, 2, 3, 5, 6, 7, 8, 9, 10, 11, 12 | |
CSF2 | 1, 2, 3, 4, 6, 7, 8, 9, 12 | 1, 2, 3, 5, 6, 7, 8, 9, 10, 11, 12 | 1, 2, 3, 6, 7, 8, 9, 12 | |
CSF3 | 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12 | 1, 2, 3, 5, 6, 7, 8, 9, 10, 11, 12 | 1, 2, 3, 5, 6, 7, 8, 9, 10, 11, 12 | |
CSF4 | 4 | 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12 | 4 | I |
CSF5 | 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12 | 1, 3, 5, 6, 7, 8, 9, 10, 12 | 1, 3, 5, 6, 7, 8, 9, 10, 12 | |
CSF6 | 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12 | 1, 2, 3, 5, 6, 7, 8, 9, 10, 11, 12 | 1, 2, 3, 5, 6, 7, 8, 9, 10, 11, 12 | |
CSF7 | 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12 | 1, 2, 3, 5, 6, 7, 8, 9, 10, 11, 12 | 1, 2, 3, 5, 6, 7, 8, 9, 10, 11, 12 | |
CSF8 | 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12 | 1, 2, 3, 5, 6, 7, 8, 9, 10, 11, 12 | 1, 2, 3, 5, 6, 7, 8, 9, 10, 11, 12 | |
CSF9 | 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12 | 1, 2, 3, 5, 6, 7, 8, 9, 10, 11, 12 | 1, 2, 3, 5, 6, 7, 8, 9, 10, 11, 12 | |
CSF10 | 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12 | 1, 3, 5, 6, 7, 8, 9, 10, 12 | 1, 3, 5, 6, 7, 8, 9, 10, 12 | |
CSF11 | 1, 2, 3, 4, 6, 7, 8, 9, 11, 12 | 1, 3, 5, 6, 7, 8, 9, 10, 11, 12 | 1, 3, 6, 7, 8, 9 , 11, 12 | |
CSF12 | 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12 | 1, 2, 3, 5, 6, 7, 8, 9, 10, 11, 12 | 1, 2, 3, 5, 6, 7, 8, 9, 10, 11, 12 |
umn of intersection for CSF4 includes 4 alone.
CSFs | Reachability set | Antecedent set | Intersection | Level |
---|---|---|---|---|
CSF1 | 1, 2, 3, 5, 6, 7, 8, 9, 10, 11, 12 | 1, 2, 3, 5, 6, 7, 8, 9, 10, 11, 12 | 1, 2, 3, 5, 6, 7, 8, 9, 10, 11, 12 | II |
CSF2 | 1, 2, 3, 6, 7, 8, 9, 12 | 1, 2, 3, 5, 6, 7, 8, 9, 10, 11, 12 | 1, 2, 3, 6, 7, 8, 9, 12 | II |
CSF3 | 1, 2, 3, 5, 6, 7, 8, 9, 10, 11, 12 | 1, 2, 3, 5, 6, 7, 8, 9, 10, 11, 12 | 1, 2, 3, 5, 6, 7, 8, 9, 10, 11, 12 | II |
CSF4 | 4 | 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12 | 4 | I |
CSF5 | 1, 2, 3, 5, 6, 7, 8, 9, 10, 11, 12 | 1, 3, 5, 6, 7, 8, 9, 10, 12 | 1, 3, 5, 6, 7, 8, 9, 10, 12 | |
CSF6 | 1, 2, 3, 5, 6, 7, 8, 9, 10, 11, 12 | 1, 2, 3, 5, 6, 7, 8, 9, 10, 11, 12 | 1, 2, 3, 5, 6, 7, 8, 9, 10, 11, 12 | II |
CSF7 | 1, 2, 3, 5, 6, 7, 8, 9, 10, 11, 12 | 1, 2, 3, 5, 6, 7, 8, 9, 10, 11, 12 | 1, 2, 3, 5, 6, 7, 8, 9, 10, 11, 12 | II |
CSF8 | 1, 2, 3, 5, 6, 7, 8, 9, 10, 11, 12 | 1, 2, 3, 5, 6, 7, 8, 9, 10, 11, 12 | 1, 2, 3, 5, 6, 7, 8, 9, 10, 11, 12 | II |
CSF9 | 1, 2, 3, 5, 6, 7, 8, 9, 10, 11, 12 | 1, 2, 3, 5, 6, 7, 8, 9, 10, 11, 12 | 1, 2, 3, 5, 6, 7, 8, 9, 10, 11, 12 | II |
CSF10 | 1, 2, 3, 5, 6, 7, 8, 9, 10, 11, 12 | 1, 3, 5, 6, 7, 8, 9, 10, 12 | 1, 3, 5, 6, 7, 8, 9, 10, 12 | |
CSF11 | 1, 2, 3, 6, 7, 8, 9, 11, 12 | 1, 3, 5, 6, 7, 8, 9, 10, 11, 12 | 1, 3, 6, 7, 8, 9 , 11, 12 | |
CSF12 | 1, 2, 3, 5, 6, 7, 8, 9, 10, 11, 12 | 1, 2, 3, 5, 6, 7, 8, 9, 10, 11, 12 | 1, 2, 3, 5, 6, 7, 8, 9, 10, 11, 12 | II |
CSFs | Reachability set | Antecedent set | Intersection | Level |
---|---|---|---|---|
CSF1 | 1, 2, 3, 5, 6, 7, 8, 9, 10, 11, 12 | 1, 2, 3, 5, 6, 7, 8, 9, 10, 11, 12 | 1, 2, 3, 5, 6, 7, 8, 9, 10, 11, 12 | II |
CSF2 | 1, 2, 3, 6, 7, 8, 9, 12 | 1, 2, 3, 5, 6, 7, 8, 9, 10, 11, 12 | 1, 2, 3, 6, 7, 8, 9, 12 | II |
CSF3 | 1, 2, 3, 5, 6, 7, 8, 9, 10, 11, 12 | 1, 2, 3, 5, 6, 7, 8, 9, 10, 11, 12 | 1, 2, 3, 5, 6, 7, 8, 9, 10, 11, 12 | II |
CSF4 | 4 | 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12 | 4 | I |
CSF5 | 5, 10, 11 | 5, 10 | 5, 10 | |
CSF6 | 1, 2, 3, 5, 6, 7, 8, 9, 10, 11, 12 | 1, 2, 3, 5, 6, 7, 8, 9, 10, 11, 12 | 1, 2, 3, 5, 6, 7, 8, 9, 10, 11, 12 | II |
CSF7 | 1, 2, 3, 5, 6, 7, 8, 9, 10, 11, 12 | 1, 2, 3, 5, 6, 7, 8, 9, 10, 11, 12 | 1, 2, 3, 5, 6, 7, 8, 9, 10, 11, 12 | II |
CSF8 | 1, 2, 3, 5, 6, 7, 8, 9, 10, 11, 12 | 1, 2, 3, 5, 6, 7, 8, 9, 10, 11, 12 | 1, 2, 3, 5, 6, 7, 8, 9, 10, 11, 12 | II |
CSF9 | 1, 2, 3, 5, 6, 7, 8, 9, 10, 11, 12 | 1, 2, 3, 5, 6, 7, 8, 9, 10, 11, 12 | 1, 2, 3, 5, 6, 7, 8, 9, 10, 11, 12 | II |
CSF10 | 5, 10, 11 | 5, 10 | 5, 10 | |
CSF11 | 11 | 11 | 11 | III |
CSF12 | 1, 2, 3, 5, 6, 7, 8, 9, 10, 11, 12 | 1, 2, 3, 5, 6, 7, 8, 9, 10, 11, 12 | 1, 2, 3, 5, 6, 7, 8, 9, 10, 11, 12 | II |
CSFs | Reachability set | Antecedent set | Intersection | Level |
---|---|---|---|---|
CSF1 | 1, 2, 3, 5, 6, 7, 8, 9, 10, 11, 12 | 1, 2, 3, 5, 6, 7, 8, 9, 10, 11, 12 | 1, 2, 3, 5, 6, 7, 8, 9, 10, 11, 12 | II |
CSF2 | 1, 2, 3, 6, 7, 8, 9, 12 | 1, 2, 3, 5, 6, 7, 8, 9, 10, 11, 12 | 1, 2, 3, 6, 7, 8, 9, 12 | II |
CSF3 | 1, 2, 3, 5, 6, 7, 8, 9, 10, 11, 12 | 1, 2, 3, 5, 6, 7, 8, 9, 10, 11, 12 | 1, 2, 3, 5, 6, 7, 8, 9, 10, 11, 12 | II |
CSF4 | 4 | 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12 | 4 | I |
CSF5 | 5, 10, | 5, 10 | 5, 10 | IV |
CSF6 | 1, 2, 3, 5, 6, 7, 8, 9, 10, 11, 12 | 1, 2, 3, 5, 6, 7, 8, 9, 10, 11, 12 | 1, 2, 3, 5, 6, 7, 8, 9, 10, 11, 12 | II |
CSF7 | 1, 2, 3, 5, 6, 7, 8, 9, 10, 11, 12 | 1, 2, 3, 5, 6, 7, 8, 9, 10, 11, 12 | 1, 2, 3, 5, 6, 7, 8, 9, 10, 11, 12 | II |
CSF8 | 1, 2, 3, 5, 6, 7, 8, 9, 10, 11, 12 | 1, 2, 3, 5, 6, 7, 8, 9, 10, 11, 12 | 1, 2, 3, 5, 6, 7, 8, 9, 10, 11, 12 | II |
CSF9 | 1, 2, 3, 5, 6, 7, 8, 9, 10, 11, 12 | 1, 2, 3, 5, 6, 7, 8, 9, 10, 11, 12 | 1, 2, 3, 5, 6, 7, 8, 9, 10, 11, 12 | II |
CSF10 | 5, 10, | 5, 10 | 5, 10 | IV |
CSF11 | 11 | 11 | 11 | III |
CSF12 | 1, 2, 3, 5, 6, 7, 8, 9, 10, 11, 12 | 1, 2, 3, 5, 6, 7, 8, 9, 10, 11, 12 | 1, 2, 3, 5, 6, 7, 8, 9, 10, 11, 12 | II |
One of the main purposes of any ISM application is to classify the investigated elements, according to their driver and dependence power, into one of the four clusters (zones), namely: independent variables (drivers), dependent variables, linkage variables, and autonomous variables. independent variables category contains all variables that have a strong driving power associated with weak dependence power while, in contrast, dependent variables category contains all variables that have a strong dependence power associated with weak driving power. Linkage variables category includes all variables that have a strong dependence and driving power while Autonomous variables category is characterized by variables with weak dependence and driving power. Such a categorization helps to obtain a more detailed picture for the CSFs in order to interpret the interaction among them clearly and in a more logical approach.
In this paper, CSFs for six sigma implementation were investigated through the developed ISM model. The developed model provides a road map that assists the practitioners to understand the process through which six sigma is practiced in a certain enterprise. However, one cannot generalize such a result within the automotive service industry although it gives insight on how SCFs are interacting in one of the largest automotive service providers in Saudi Arabia. Practices of six sigma implementation are still in need to be critically investigated independently (i.e. case studies). A single firm may have its own approach of implementing and practicing six sigma. However, even though the studied case was selected from the automotive service industry, the outcome of this study supports the results of previous empirical studies in a sense that all factors for six sigma implementation are, in fact, critical (i.e. none of them is located within the autonomous category). Nevertheless, there is still a room for statistical validation. Specifically, the developed ISM model is in need of statistical validation that can be conducted using the Structural Equation Modeling (SEM). ISM can be employed to represent theoretical platform on which SEM can be implemented in a more confident manner. Such a recommendation has also been proposed by Singh and Kant [
The author would like to thank King Abdulaziz University (KAU), Jeddah, Saudi Arabia, for providing the required support in order to conduct and publish this paper. The author also would like to thank Mr. Saleh Mahjoub, Mr. Rakan Maghrabi, and Mr. Faisal Almarwani for their efforts in collecting data.