ahp-class
DESCRIPTION
AHPTRANSCRIPT
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Selection of School
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Selection of School
Selection of School:
Academic Reputation, Location,
Placement, Fees, Infrastructure
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Analytic
Hierarchy Process
by
G N Patel
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Admission
Location PlacementReputation Fees Infrastructure
YX Z
CRITERIA
ALTERNATIVES
Hierarchic
Thinking
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Purchase of apple
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Purchase of apple
Purchase of Apple:
Taste, Aroma, Ripeness, Size, Price
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Purchase of Oven
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Purchase of Oven
Choose best oven:
function, economy,
safety and reliability,
convenience
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Whom to marry
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Whom to marry
Whom to marry:
flexibility, independence,
commitment, humor,
intelligence, physical,
socio-cultural
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Selection of Job
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Selection of Job
Selection job:
salary, life quality of the city where
job is located, job profile, nearness to home, security,
reputation, flexibility (time, work place), opportunity
(salary potential, top level position)
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Evaluation of Employees for Promotion
Evaluation of employees for promotion:
dependability, education, experience,
quality, attitude, leadership
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Perhaps the most creative task in making
a decision is to choose the factors that
are important for the decision
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Analytic Hierarchy Process (AHP)
A popular mathematical method for solving MCDM problems .
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AHP Applications
It has been used in more than 30 diversified field like
1. Planning and development
2. Selection
3. Resource allocation
4. Forecasting
5. Evaluation
6. Priority and ranking.
7. Health and related fields
and many more.
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Importance of AHP
It provides a unique way of incorporating qualitative and quantitative judgments.
It is able to rank choices in their order of effectiveness in realizing their objectives.
It allows decision makers to include inconsistency in their choices.
It is versatile and flexible to enable a combination of other mathematical methods not limited to LP, Fuzzy logic
theories and network models.
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Analytical Hierarchy Process
1.A multi-attribute analysis technique that
organizes complex systems/unstructured
problems with many elements of different
influence.
2.Easy to use, automatable algorithm,
well-accepted by policy makers.
3.Uses stakeholder perceptions to find the
most important elements influencing
complex decisions (only as good as the
experts).
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The Analytic Hierarchy
Process (AHP)
Decision Making involves setting priorities and the AHP is the
methodology for doing that. It is designed for situations in which
ideas, feelings, and emotions affecting the decision process are
quantified to provide a numeric scale for prioritizing the
alternatives.
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AHP- Methodology
It has the following steps:
Step 1.
Stating the goal, criteria, sub- criteria, alternatives and
constraints of the problem clearly.
Step 2.
Arrange fragmented decision problems into (tree- like)
hierarchy structure of different levels ( goal, criteria, sub-
criteria, alternatives.)
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The Analytic Hierarchy Process (Step 2 contd.)
Objective
Criterion 2Criterion 1 Criterion KLevel 2
Subcriterion 1 Subcriterion 2 Subcriterion K
Alternative 1 Alternative 2 Alternative N
Level 3
Level P
Hierarchy with P Levels
Level 1
Step 2. Decompose the problem into a hierarchy of interrelated
decision criteria and alternatives
.
.
.
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GOAL
CRITERIA
ALTERNATIVES
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Relative Measurement
The Process of Prioritization
Step 3.
Develop a pair wise comparison matrix using fundamental scale to
measure both tangible and intangible criteria.
In relative measurement a preference, judgment is expressed on
each pair of elements with respect to a common property they
share.
In practice this means that a pair of elements in a level of the
hierarchy are compared with respect to parent elements to which
they relate in the level above.
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The Principle of the AHP
This comparison is carried out using the following fundamental scale from 1 to 9 as follows: 1 Equally preferred
2 Equally to Moderately preferred
3 Moderately preferred
4 Moderately to Strongly preferred
5 Strongly preferred
6 Strongly to Very Strongly preferred
7 Very Strongly preferred
8 Very strongly to Extremely preferred
9 Extremely preferred
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AHP- Methodology(Contd)
The pairwise comparison matrix looks like
where is the relative importance of criterion i over criterion j number of comparisons required for the pair-wise comparison matrix is
given by n(n-1)/2 where n = number of elements
Diagonal elements are 1 and other elements are reciprocals of earlier comparisons that is
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AHP- Methodology(Contd)
Step 4
The priority vector w is obtained by using Additive Normalization as follows:
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Consistency of the Comparison Matrix
Step 5 : Testing the consistency of the comparison matrix
If all the columns of the normalized matrix are identical, then the
original matrix is said to be consistent
is a consistent matrix
Consistency implies coherent judgment on the part of the decision
maker regarding the pair-wise comparisons.
R L
A= R 1 5
L 1/5 1
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Consistency of the Comparison Matrix
Step 5 : Testing the consistency of the comparison
matrix
Mathematically, A is consistent if
Also it can defined as when n is the size of the matrix
and A is consistent.
When A is not consistent , than , max being the
principal eigen vector
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Consistency of the Comparison Matrix
(contd.)
Step 5
Testing of the consistency
Where max = principal eigen vector
CI = consistency index
RI = the random consistency index.
.
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Consistency of the Comparison Matrix
(contd.)
It is unusual for all comparison matrices to be consistent.
Indeed, given that human judgment is the basis of the
construction of these matrices, some reasonable degreeof inconsistency is expected and tolerated.
The matrix is accepted as consistent if
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AHP- Methodology(Contd)
Step 6: Global weights of alternatives with respect to the goal defined in the AHP model are calculated.
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Selection of Management Institute for EDP/FDP
Ms. Y has received information from three Management
institutions A, B, C to attend EDP / FDP on similar topics. She
specifies two main criteria location and academic reputation.
Being a participant believing to enhance knowledge through
attending such programmes, she judges academic reputation to
be five times as important as location. Using the symbols R and
L to represent reputation and location, the associated
comparison matrix is given as
R L
A= R 1 5
L 1/5 1
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Example Contd.
The relative weights of the alternatives of A,B and C
within each of the L and R criteria, whose elements
are based on Ms Xs judgment regarding the relative importance are as follows:
L A B C
A 1 1/2 1/5
AL= B 2 1 1/2
C 5 2 1
A B C
A 1 2 3
AR= B 1/2 1 3/2
C 1/3 2/3 1
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Pros and cons of AHP
Pros
Hierarchical structuring of a decision problem
Combining multiple inputs from several persons to a consolidated
outcome
People usually agree with the out coming process
Calculations using excel
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Pros and cons of AHP
Cons
Pair wise comparison is a quite artificial way a set of items. People
are more use to agree-disagree or ranking
If consistency index is too high: request to reconsider
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Recommendations
When using AHP: Try to structure the model in group of max 4-5
criteria or sub criteria. If possible introduce additional hierarchical
levels
Spend time to explain the use of scale for pair wise comparisons
without knowledge of AHP. Ask them to use the whole range 1 to 9.
Even with a consistency value above the recommended limit, the
results usually reflects the correct ranking and still can be used.
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Recommendations
AHP is ideal to get a consolidated result for inputs from several
participants using the geometric mean
Once AHP is introduced and used as method for decision making,
results are generally accepted, as the method is based on
mathematics, seen as neutral and objective