One of the main points when implementing the Information Technology Infrastructure Library (ITIL) is which order the processes must be implemented. In the systematic literature review (SLR) developed, it is possible to find references about strategies and factors that ease the implementation of the ITIL, static sequences for the processes to be implemented, and recommendations about the first process to implement, but it is rather complicated to find references that explicitly define the order (adapted to a specific company) of the processes to be implemented. Thus, once it is shown that there is no methodology/algorithm providing a sequence of ITIL processes specifically adapted for each company, an algorithm to solve this problem is presented: The algorithm has a deep mathematical basis and returns a sequence of ITIL processes to optimize the efforts during implementation, so the company implementing the ITIL gets the closest to the competitors. The optimization is made considering parameters such as staff, age of the company, IT size, industry, etc. Thus, the sequence proposed is specific for each company. Finally, a comparative of the sequence obtained (from the proposed algorithm) with sequences discovered in the SLR is presented and applied to a real case.

There is no doubt about the importance of information resources in organizations. The management of organizations may be very different from one to another but in all cases the quality of IT (information technology) services is directly dependent on common principles, such as adding value, improvement of customer satisfaction and productivity, and/or reducing costs [

The main goal of an IT manager is providing the best quality service with fewer resources as possible, and achieving parameters of efficiency, time, cost, etc. To do it, it is possible to adopt and adapt several standards, good practices handbooks, and rules [

The Information Technology Infrastructure Library (ITIL) is a market standard practices library completely oriented to services and its management, development, and operation [

Currently, ITIL is divided in five groups of processes (service strategy, service design, service transition, service operation, service continual improvement) but ITIL does not define a strategy to implement the processes: No order of processes is presented, no dependency on the company where ITIL is implemented, no dependency on the industry, etc. It just includes the processes needed for proper management of IT Services [

There is much interest in companies about ITIL implementation [

There are several studies which make approaches around ITIL implementation and how this implementation should be conducted. These studies consider different points of views [

Summarizing, authors focus their attention on next issues [

Thus, there is not a clear approach to define the strategy to implement the ITIL. It does not matter if we look at the steps, the sequence, the factors, the characteristics of organizations, or if we look at specific issues that may affect the implementation; there is not a clear solution for companies wishing to implement the ITIL. This leads us to one of the main problems to solve [

This article presents a study that started with a systematic literature review (SLR) to discover how ITIL processes are ordered by the companies during the implementation phase. Once it was found that no algorithm was used to order processes, we set up the math basis for the optimal ordering algorithm presented in this article. Following this, we built the database (filled up with data from real companies—see

A systematic review of literature to get a deep understanding of the state of art was developed. The references about how to perform a review can be found in [

A summary of the results of the SLR developed is presented. In order to give an overall idea of the state of art of the ITIL sequences for implementation, next strategies were identified:

Non-fixed sequences: These strategies include sequences which are objective dependent. That is, a general strategy or function to organize processes is given. This strategy or function is oriented to a specific objective—maximizing client satisfaction, minimizing implementation time, avoiding deadlocks, etc.—but they, finally, offer the same sequence for every company having the same objective.

Static sequences: This second group of strategies define a fixed sequence which is common to every implementation. That is, independently of the size, type, industry—or whatever factor—of the company, the same ITIL sequence is defined. These strategies are usually based on criteria such as polling to experts, dependencies between processes, among others.

Implementation examples and critical success factors: The third group of strategies are focused on defining which factor affects the success or the failure of an ITIL implementation. This group also includes those strategies that define rules and methodologies of implementation based on previous cases of real implementations.

These groups of strategies to implement the ITIL are explained in the next paragraphs, based on the literature review developed previously.

A fuzzy logic-based proposal is presented in [

The proposal [

The approach of [

A compilation work is presented in [

The reference [

In [

A first model of isolated ITIL processes.

Another model that contains the dependencies between ITIL processes.

A final model to relate the capacity level of the processes and the maturity level of the organization. One of the main characteristics of this proposal is the combination of concepts of the ITIL and Capablity Maturity Model Integration (CMMI) to propose a sequence.

It could be thought that this proposal describes a dynamic sequence, but in fact the result is a fixed (or very close to be fixed) sequence. The reason is that the second model of the mentioned above, determines which processes should be implemented to implement the next one; so only slight differences in the initial processes can be found. Once these ones have been implemented, the rest of the sequence hardly vary from one organization to other.

A fixed sequence of implementation is also shown in [

In some cases, the objective is not to define explicitly a sequence but, rather, address a starting point, which means defining the first process to implement. This is the case in [

(a) Critical success factors: Another research area is composed by those authors who try to identify success factors on ITIL implementation: [

It is possible to identify also a group of works that provide methodologies and strategies to implement the ITIL [

A different view is proposed in [

A compilation work can be found in [

A vast, extensive work is presented in [

A methodology based on business process change (BPC) is explained in [

(b) Strategies: Regarding strategies, [

In [

As it has been shown before, there is no any specific approach offering a methodology, neither an algorithm to define the complete order of processes when implementing the ITIL. This means: (a) No algorithm for non-fixed sequences has been published; and (b) no algorithm for an optimal sequence specifically adapted for each company has been published.

This conclusion leads us to the define the algorithm presented in the next paragraph, where we present how to optimally order the ITIL processes for a specific company depending on: (a) The level of implementation of the ITIL it has already reached; and (b) on the characteristics of the company.

The algorithm presented here assumes that a set of companies and its characteristics (size, industry, age, etc.) are available. The objective is to define an algorithm that maximizes the position of a company compared with its competitors in terms of ITIL implementation. The selection of processes to implement depends on the strategic needs of the company and the degree of implementation of every ITIL process compared to the competitors. The algorithm selects the process that maximizes the benefits of ITIL implementation in front of its competitors.

Let _{e}

Let

Let _{ne}_{e}

It will be noted by _{sel}

Let us denote by _{p}_{ITIL}

Let _{ITIL}

Let _{i}_{ITIL}_{i}_{i}

The possible value of _{i}_{m}_{i}_{i}_{m}.

For example, the _{1} condition could mean that the process is not implemented, neither will it be in the long term; in that case _{1}(_{i}_{i}_{i}

It should be noticed that {1..._{i}

Let _{v}_{1}, _{2}, …, _{v}

Following this, let us define the domain of each parameter that belongs to _{v}_{k}_{k}.

Next, let us define every _{1}, _{2}, …, _{v}_{ij}_{i}

In such case, the

Next, _{i}_{1j} is defined as the average of the assessment of the _{i}_{1} = _{1k}:

In a general way, the average of the assessment of the _{i}_{j}_{jk}_{ijk}

Or, expressed in a more formal way:

This means that the average of the assessments _{i}_{i}_{e}_{j}_{j}_{e}_{jk}.

At this point, it is possible to show the algorithm that allows any company to decide which process should be first implemented.

Let us define _{sel}

In order to decide which process should be first implemented, it is necessary to define a parameter containing information about the implementation of an ITIL process in other companies with similar characteristics. To define it, and taking in consideration the definitions presented in previous paragraphs, the next parameters are needed; where _{ijk}_{i}_{sel}

In this expression, _{i}_{i}

It can be seen how _{ijk}_{i} process, the distance between the maximum value _{jk}_{sel}_{i}_{sel}

It is necessary to define an indicator or parameter to help us to decide the best process to be implemented next. This indicator should take high values when the relative position (in terms of implementation of a process) is better than the reference companies denoted by _{sel}_{sel}

Let

This indicator can be particularized for a particular process _{i}_{sel}_{i}_{sel}_{i}

This expression calculates _{i}^{2} value for each group of companies that satisfy the condition of having the same characteristics as _{sel}_{i}_{i}_{sel}_{i}_{ijt}j_{i}_{sel}

As a consequence, if the _{i}_{sel}_{sel}_{i}_{sel}_{i}

Thus, we can formalize _{i}_{i}_{i}

Thus, _{i}_{i}_{x}_{i}

Once this indicator is defined, it is possible to define the selection criteria for the first process to be implemented:

This expression means that the best process and the one that should be first implemented, that is, the one that will most improve the rank of the company (in terms of ITIL implementation) compared to the competitors, is the one with the lowest value for _{p}

The criteria shown previously needs a small correction: Due to the fact that relative positioning _{i}_{i}

Thus, if we select iteratively the _{opt}_{opt}

As mentioned before, there is not a generic methodology to sequence ITIL processes which takes into consideration the parameters of each company. A solution for this has been developed and it lays on data gathered from different companies. This information allows a candidate sequence to be proposed for a company depending on the size, industry, age, and other parameters. Of course, this solution generates a sequence for each company that aims to implement ITIL.

It is necessary to compare the results of such optimal implementation with the sequences obtained in the literature review. The objective of this comparative is to determine if the sequence is significantly different from the ones proposed by different authors. The proposals of sequence selected are S1: [

To determine if the proposed sequence and the reference sequence are independent, Spearman contrast and Kendall contrast were used. In both cases the null hypothesis is that both sequences (the reference one and the proposed one) are independent; and the alternative hypothesis is that both sequences are related (that is, there is not a significant difference). The level of confidence used was α = 0.1.

For every real company, an optimal sequence is obtained and, so, the comparation with the referenced sequences may lead to one of next results: The optimal sequence is significantly different from the reference sequence or the optimal sequence is not significantly different from the reference sequence. In addition, even in this second case it may occur that selected processes for implementation are the same, but they are selected in a smoothly different order (not statistically different).

As an example, a real, small, and young IT consultancy company located at Madrid (Spain) with less than nine employees was selected for testing. The algorithm is required to propose an optimal sequence considering five criteria (staff, IT employees, company age, industry, area). The application of the algorithm requires a database with data from other companies and make calculations with them (more information about this issue in

1—continuous improvement; 2—management of catalogue; 3—incident management; 4—validation and testing; 5—availability management; 6— service portfolio management; 7—financial management; 8—configuration management; 9—transition management; 10—access management.

Results of the comparative with other sequences are shown in

From

Let us remember that the optimal sequence selects processes iteratively, so the global degree of the ITIL implementation on a company is maximized when compared with similar companies in terms of size, IT size, age, industry, etc. This optimal sequence is significantly different from the published sequences by different authors.

The significance of the experiment is based on the fact that companies obtain a sequence of processes to implement ITIL at very low cost (no experts are needed), defining the criteria for optimization and considering the degree of implementation already reached at the moment.

The proposed algorithm offers a sequence of ITIL processes that in most cases is different from the known existing proposals. This approach has benefits, listed below:

The proposed sequence is obtained from a mathematical model, so it does not depend on the opinion of experts—as most of the proposals in the literature review do—neither on subjective issues. This is a valuable point, because not all companies (especially small companies) can afford to pay a set of experts to decide how to implement processes of the ITIL. This is also a valuable issue as it avoids ambiguity and subjective opinions and leads to a repeatable process for the estimation of the best sequence for a company.

The proposed sequence is obtained so the order of processes proposed maximizes the efforts of implementation: It gets the company the closest to competitors, if the implementation of ITIL processes in that company is far from the average, and it gets the company to a better position even if it is over the average. Due to the calculation of the relative position factor and its optimization, the process selected in every iteration is the one that optimizes the positioning in terms of ITIL implementation.

The company may select the criteria to optimize efforts of implementation: size, age, region, etc. Thus, every company will obtain different sequences especially set for each one. As no approach defining a sequence that depends on characteristics selectable by the company has been found, this functionality represents an advantage; companies can decide what are the most important factors when implementing the ITIL and can obtain a sequence that best fits its needs.

The solution proposed will get more accurate as the database is filled with more and more company data. The database used with the algorithm has information about five parameters of each company, as well as the value of the degree of implementation of every ITIL process: As more data it added, a better solution is produced from the algorithm, as more information is known about what other companies are doing (about ITIL implementation)

Comparatively, this solution may be (and really it is) implemented in a software platform which is easier and cheaper than considering experts, as some approaches do. As it has been said before, the algorithm has a mathematical basis which simplifies its implementation in a software program.

Due to fact that the solution proposed is specific for each company, a higher satisfaction of clients is expected (companies implementing the ITIL).

Although it is not a benefit of the algorithm itself, the software platform used offers a comparative with other proposals. Based on this comparison, the statistics tests show how different this proposal is from other approaches.

On the other hand, the algorithm needs a database with characteristics of companies and the degree of implementation of every ITIL process, so the geographic limitation on its use could be considered a disadvantage. In the real case analyzed, the data for the database was obtained from Spanish companies. Anyway, the algorithm is valid once a data set for that specific region is available. Just an update of data makes the algorithm useful in other regions.

The selection of ITIL processes to be implemented is quite important in order for it to succeed. The literature about how to implement the ITIL is huge, but there is no a common approach about the selection neither the order of processes. The main approaches are: (a) A fixed sequence independent of the characteristics of the company; (b) a non-fixed sequence, in these cases there is a great influence of internal or experts opinions about the order of processes; and (c) to pay attention to factors that may help to succeed but without explicitly defining a sequence.

After the literature review, a model for selection was presented, which was based on selecting the process that places the company the nearest to competitors, taking in consideration several factors as size, industry, market, IT size, etc. This proposal is referred to as optimal as it minimizes the distance between the company (in terms of ITIL implementation) and the rest of similar companies. The main advantage of this selection algorithm is that it allows the implementation to be optimized, taking into consideration the different characteristics or parameters of the company. In the literature review, no algorithm was found that allows an implementation sequence to be obtained in such a way.

Although extending the testing of the algorithm to more and more companies is needed, the initial results show that this different algorithm really produces a different sequence of processes. The initial comparison with other techniques shows that sequences are statistically different, and the companies obtain the optimal sequence to get the closest to competitors, as the selection algorithm is designed to do so.

Of course, the algorithm needs a database of companies with its characteristics and the degree of implementation for every ITIL process, as that is the basis to optimize the sequence proposed. Anyway, the database value improves with every company that is introduced, as that results in a better proposal of sequence.

For the small IT consultancy company examined, the results show that the new optimal sequence is significantly different from the existing ones. Future works are oriented to test the algorithm on more companies to get an idea of the overall discrepancies between the proposed sequence and the reference approaches.

Conceptualization, J.L.R.; methodology, J.L.R.; software, J.L.R.; validation, M.A.; formal analysis, J.L.R.; investigation, J.L.R. and M.A.; writing—original draft preparation, J.L.R.; writing—review and editing, M.A. All authors have read and agreed to the published version of the manuscript.

This research received no external funding.

The authors declare no conflicts of interest.

The data for the database as obtained from a poll.

Description of the polling.

Concept | Value |
---|---|

Scope | Spain |

Universe | Companies with more than one employee |

Type of polling | Web form |

Sent | 200 |

Minimum to be significant | 64 |

Confidence level | 90% |

Population | 200.000 |

Error | <8.5% |

Company selection | Random |

Mode | Single-phase |

Comparative proposed sequence–reference sequence.

Reference Sequence | Spearman Contrast |
Spearman Contrast |
---|---|---|

S1 | 0.35/0.39 | 0.05/0.28 |

S2 | 0.05/0.34 | 0.12/0.24 |

S3 | 0.38/0.53 | 0.05/0.04 |

S4 | 0.22/0.36 | 0.13/0.26 |

S5 | 0.08/0.80 | 0.20/0.73 |

S6 | 0.63/0.56 | 0.15/0.46 |