Weight Uncertainties in AHP-OS

It is now possible, to analyse the weight uncertainties in your AHP-OS projects. When you view the results (View Result from the Project Administration Menu), you see the drop-down list for different AHP scales and a tick box var is shown.

Tick var and click on Scale. All priority vectors of your project will display the weight uncertainties with (+) and (-).

For example, “Capital” has a priority of 15.0% with an uncertainty 0f +1.7% and -2.1%.

The diagram for the total result will show in green the calculated priorities, in dark and light grey the possible plus and minus variations. 

Calculation is based on a randomised variation of all judgment inputs by +/- 0.5 on the 1 – 9 judgment scale. For more than 1 participant the variation is reduced by the square root of the number  of participants.

When downloading the results as csv file, uncertainties are listed below the group result.

 

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AHP Judgment Scales

The original AHP uses ratio scales. To derive priorities, verbal statements (comparisons) are converted into integers from 1 to 9. This “fundamental AHP scale” has been discussed, as there is no thoretical reason to be restricted to these numbers and verbal gradations. In the past several other numerical scales have been proposed [1],[3]. AHP-OS now supports nine different scales:

  1. Standard AHP linear scale
  2. Logarithmic scale
  3. Root square scale
  4. Inverse linear scale
  5. Balanced scale
  6. Balanced-n scale
  7. Adaptive-bal scale
  8. Power scale
  9. Geometric scale


Fig. 1 Mapping of the 1 to 9 input values to the elements of the decision matrix.

Power scale and geometric scale extend the values of matrix elements from 9 to 81 resp. 256. Root square and logarithmic scale reduce the values from 9 down to 3 resp 3.2. Inverse linear and balanced scale keep the values in the original range, but change the weight dispersion. The balanced-n scale is a corrected version of the original balanced scale. The adaptive-bal scale scales the values depending on the number of criteria: for n = 2 criteria it represents the balanced scale, for n = 10 criteria it represents a balanced power scale.

As a result, priority discrimination will be improved using the geometric or power scale, but at the same time the consistency ratio will go up. For the  logarithmic, root square, and inverse linear scales it is the opposite, priorities are more compressed or “equalised” across the criteria, see Fig. 2. At the same time CR improves.

Only the balanced-n scale and adaptive-bal scale will improve (or at least keep) the consistency ratio in a reasonable range and at the same time minimise weight uncertainties and weight dispersion.


Fig. 2 Change of priorities for different scales for an example with eight criteria.

The choice of the appropriate scale is difficult and an often discussed problem. Until today there is no published guideline, when to select which scale. A study on the impact on priorities and consistency ratio (CR) is published in [2]. I have just recently submitted a paper, providing a guideline on the selection of different AHP scales.

How to select different scales in AHP-OS

Open a project with completed judments (participants) from your project list. In the Project menu click on View Result. By default the results are then shown calculated based on the standard AHP 1 to 9 scale. To recalculate for different scales, select the scale in the Group Result menu from the scroll down list and click on Scale.

References

[1] Ishizaka A., Labib A. Review of the main developments in the analytic hierarchy process, Expert Systems with Applications, 38(11), 14336 - 14345, (2011)

[2] Jiří Franeka, Aleš Krestaa. Judgment scales and consistency measure in AHP, Procedia Economics and Finance, 12, 164 - 173 (2014)

[3] W.W. Koczkodaj. Pairwise Comparison Rating Scale Paradox, Cornell University Library, (2015) https://arXiv.org/abs/1511.07540

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AHP-OS Data Download and Import in Excel

Most data generated with AHP-OS can be downloaded as csv files for import into a spreadsheet program and further analysis:

  • From the Hierarchy Input Menu – decision hierarchy and local & global priorities
  • From the Group Result Menu – Priorities by node and consolidated decision matrix
  • From the Project Data Menu – Decision matrices from each participant

For each download you can select “.” or “,” as decimal separator. The downloaded csv (text) file is coded in UTF-8 and supports multi-language characters like Chinese, Korean, Japanese and of course a variety of Western languages.

How to import into excel?

Open Excel, click on “File” -> “New” to have a blank worksheet. Click on “Data“. On the left top you will find the “Get External Data” box.

Click on From Text to select the downloaded cvs file for import. The Text Import Wizzard will open.

Now it is important to select 65001 : Unicode (UTF-8) under File origin.

Then, depending on your decimal separator, select Comma or Semicolon as Delimiters:

When the import is done, your text characters should be displayed correctly.  Save the file “Save as” as Excel workbook (*.xlsx).

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AHP-OS – Editing saved projects

In the project menu of the latest AHP-OS version (2017-05-25), I added a button to edit saved projects. As long as there are no participants’ inputs (completed pairwise comparisons), any saved project’s hierarchy, alternatives or description can be modified.

Open a project from your project list, and click on Edit Project. The project hierarchy page will open with a message on top , indicating that you are modifying an existong project. You can now change the hierarchy, for example add criteria or alternatives. A click on Save/Update in the Hierarchy Input Menu

will overwrite the data of the original project under the same session code. You will see it in a message . Before you click on Go to save,  you  can also update the project short description:

Difference between Use Hierarchy and Edit Project

With Use Hierarchy in the project administration menu, the hierarchy window will open, and you can also modify the hierarchy or alternatives. But in contrast to Edit the modified project will be saved as a new project under a new project session code.


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AHP-OS and Farsi

Thanks to the feedback of a user from Iran, I found out that AHP-OS is working with RTL fonts like Farsi. It is important to add the semicolon to the right end of a node definition, and use latin punctuation marks, for example:

کاربری: مسکونی , تجاری , اداری ;

A simple decision hierarchy example looks like here:

farsi

Unfortunately, I am not able to check for a hierarchy with more than one level. If anyone could provide a 2 level hierarchy, I would appreciate. Arabic fonts should work too; kindly contact me, if you have an example.

 

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Group Decision Making with AHP-OS

My AHP free online software AHP-OS has a feature to involve a group of decision makers to give their inputs to a decision problem. In contrast to my AHP Excel template, in AHP-OS the number of participants is practically unlimited. As of now, I see users having up to 100 participants in one project.

How to use AHP-OS for Group Decision Making?

As registered user you need to start with a new project by defining your decision hierarchy. In the Project Administration Menu click on New, define your hierarchy, Submit and Save as project. You have the possibility to give a short project description, explaining the project, before it is saved.

Once saved, you will be automatically brought back to your project page, and the project will be shown on top of your project list.

grdecproject

The session code is a unique code identifying the project. When you click on the session code link, the Group Session Input screen will open, and you see a message like “Hierarchy evaluation. Session code EvUhUn Session Chair: Klaus. Project has 0 participants’ inputs. You are participating as Klaus.” Now you can either participate yourself as a decision maker in the project, or get a link to provide to your participants for their inputs.

Participating by yourself as a member of the group

Simply click on the AHP button to start the pairwise comparisons, and – once completed – click on Submit for group eval to submit your inputs.

Provide a link to let others participate as members of the group

In the group input menu click on Leave group input mode and confirm ok to leave the input mode without submitting your pairwise comparisons in the pop-up window.

groupinpmenu

Now you will see the link that you can copy/paste and send to your group members for their participation in the project.

grouplink

Click on Done in the Active session menu to go back to your project list.

Participants input

Your participants don’t need to be registered users. If you want to test by yourself, you need to logout from AHP-OS, before you open the group link.

When your participants open the link, they will be asked for their name, before they can start their pairwise comparisons. They will then see the decision hierarchy with a red lined AHP button and  a message “Click on AHP to complete pairwise comparisons. Click on Submit for group eval once completed.”

grhier1

Now they can start their pairwise comparisons. When completed, all AHP buttons and priorities will be marked green.

grhier2

After a click on Submit for group eval the AHP button disappears and a message “Ok. Data were submitted. Thank You for your participation!” is displayed.

Group results

Once you have participants submitted data, a click on the session code link in your project list will automatically bring you to the group result page. As a participant you will get a button View group result in the Group input menu.

groupinpmenu1

The group result page gives you on top the project data and list of all participants. Individual participants can be selected or deselected to analyze the group results in further details.

projdata  partlist

The next sections of the group result page shows the decision hierarchy with consolidated priorities, a breakdown by nodes (categories) with priorities for the node and the consolidated (aggregated) decision matrix. It also shows the AHP consensus indicator as a measure of group consensus.

grresult

Input data for each participant is available under View Input Data in the group result menu:

groupresmenu

For you as chair of the group session, it is also possible to download data as csv text file for further processing in a spreadsheet program. With Use consol. priorities you now can define Alternatives with the consolidated priorities of selected participants.

 

 

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AHP Online Software CSV Data Export

AHP-OS allows for downloading your project data as a comma separated value text file. The following menus include a csv download key:

  • Hierarchy Input Menu – download the AHP hierarchy
  • Group Result Menu – download resulting priorities and consolidated (aggregated) decision matrix
  • Project Data Menu – download decision matrices for all individual participants

Depending on your regional settings of your PC, for each download you can select the decimal point or decimal comma as decimal separator.

Text encoding of the CVS file is UTF-8. If you are using country specific characters and Windows Excel, you can convert from UTF-8 to ANSI. Open the CSV file with notepad, and save as a new file with Encoding set to ANSI.

 

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AHP Online Software – Decision Matrices – Update 2016-11-02

With the latest update of my AHP-OS online software you can now view and download the decision matrices of all participant. The group result menu was extended by a selection View Input Data:

g-result-menu

From there you reach the Project Detailed Input page, which shows the decision matrix for each individual participant and all nodes of the hierarchy:

projectinputdata

The project data menu has the button to download the data in csv format:

p-data-menu

The csv file contains the basic project data – Session Code, Project Name, Project description, Author, Date, Type of evaluation, Number of Participants – as well as all input decision matrices sorted by participant and nodes (categories of the hierarchy) or criteria for alternative evaluation.

With the Back link you can go back to the Group Result Page.

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AHP Online Software – Latest Update 2016-10-29

Based on the request from some users I have modified the result display of my AHP-OS online software. Beside the resulting priorities it is now possible to see the underlying consolidated decision matrix, which results from the aggregation of individual judgments (AIJ) using the geometric mean.

Decision Hierarchies

For decision hierarchies the result page shows the resulting local and global priorities (overall result) in hierarchical form, and the global priorities in descending order in a bar graph.

Then, in a breakdown by nodes, consolidated priorities, consolidated decision matrix and the priorities of individual participants are shown:

ahp-result
As in this example, the consolidated matrix for one participant is the same as the AHP decision matrix.

Alternative Evaluation

For alternative evaluation the breakdown is done by criteria. It shows the consolidated preferences for all alternatives with respect to each of the criteria:

ahp-result1

In this example the House A from the alternative houses A, B, C has the best match with respect to the criterion “Size”.

Outlook

I am now working on the extension to let you download the complete set of input values, i.e. all underlying decision matrices, to excel. In the current version only the resulting AHP priorities are available.

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AHP Frequently Asked Questions

Over the year I receive many questions about AHP, my AHP excel template and my AHP online Software. Here a selection of frequently asked questions:

General Questions

Q: I have 15 criteria and 20 alternatives, can you extend your template/software?
A: The excel template can handle up to 10 criteria, my online software is limited to 12 criteria (in one hierarchy level) and 10 alternatives. In principle it could be extended, but the limitation is inherit to the AHP method. Please read my explanations here.

Q: I have more than 10 alternatives, can I use AHP for priority evaluation of criteria and a different method for the evaluation of alternatives?
A: Yes, you can combine AHP for criteria evaluation with another method for alternative evaluation. Alternative evaluation could be done for example using a simple table with a yes/no or applicable/not applicable scale, or any other scale, e.g. Likert scale, how good the individual alternative matches the specific criterion.

Q: I have 150 participants, can I use your excel template/software?
A: My AHP excel template is limited to 20 inputs, my AHP online software can handle a (practically) unlimited number of participants. Use the AHP online software.

Q: How can I resolve the inconsistency (CR>0.1), when participants are done with their pairwise comparisons.
A: Once the pairwise comparison is done and submitted, data can not be changed and consistency ratio is what it is. Ask your decision makers to adjust their judgments  in direction of the most consistent input during the pair-wise comparisons for the highlighted three most inconsistent comparisons. Please see also my posting here.

Q: Can I use the Likert scale instead of the AHP scale?
A: No, AHP is based on the rational scale 1/9 … 1 … 9. It cannot be replaced by the Likert scale.

Q: Do you support Fuzzy AHP?
A: No, I have made no provisions to support Fuzzy AHP, neither in Excel, nor in my online software.

Q: How is the computation done, where do I find the description and formulas?
A: Please download the manual for the excel template from here, and the software description from here.

Q: How can I cite your work, can you give me a reference?
A: Please cite my paper: Implementing the analytic hierarchy process as a standard method for multi-criteria decision making in corporate enterprises–a new AHP excel template with multiple inputs

AHP Excel template

Q: Can I extend the number of participants to more than 20?
A: Though it is possible in principle, the better way is to use my AHP online software with (practically) unlimited number of participants. I will not do a further extension of the template.

Q: Do you have a version of the Excel template w/o multiple inputs?
A: Yes, a simplified version is available on request from the author.

Q: How can I do alternative evaluation using your Excel template.
A: It is not possible. The template can only handle one category of a hierarchy and calculate the priority of one set of criteria.

AHP Online software

Q: If I have a group of decision makers, do they need to register for the online software?
A: No, they don’t need to register. As the owner of a project you get a link for group decision inputs. Simply send them the link, and they can start the pairwise comparisons.

Q: Can I erase/delete inputs from individual participants from the group results?
A: Sorry, at the moment there is no possibility to erase/delete inputs of individual participants. You can open a project with participants’ input and click “Use consol. priorities”. Then “Reset priorities” and “Save hierarchy”. Then you will have the same hierarchy as a new project without participants’ input.

Q: The alternative evaluation is not working?
A: Criteria evaluation (priorities) and alternative evaluation have to be handled as two different projects. Only when you have a decision hierarchy with completed comparisons and evaluated priorities, you can define the alternatives from the group result page clicking on “Use consol. priorities”. Define number and name of alternatives from there and save as new project. Hierarchy evaluation and alternative evaluation projects appear as type “H” for the first and type “A” for the latter in your project list.

Q: Can I get the source code of your online software?
A: Sorry, it is not an open source project.

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