Concerning the deviation between the matrix result and the normalizing result, the consistency of the judgment matrix for the weightings must be checked by means of the AHP method. A consistency ratio (C.R) of 0.10 or less is considered acceptable and the formula is given by:

Where:

C.R. = Consistency ratio.

C.I. = Consistency index of a randomly generated reciprocal matrix from the scale 1to9.

l_Max = The maximum eigenvalue in the matrix.

n = The number of items.

R.I. = An average random index provided by Saaty (sample size =500).

Here the relationship between "n" and "R.I." is given:

　

It can be identified that the C.R. is 0.0625 for this case. Therefore, the consistency ratio for these particular weightings is considered acceptable.

In practice, the important comparison on each level should be done by the expert team. All the judgment matrixes can be counted and the statistical result of weighting of each item on all levels can be obtained. The suggested distribution of weighting is given in table 3.

(3) Assessment Criteria

The design of the self-assessment model depends on the requirements of the national regulations and international conventions, in particular the revised STCW Convention. The extent of items which can be assessed depends on the nature of the specific item. Some items can be directly assessed in number. However, in this model, most items cannot be directly assessed in number. Several levels may be used to describe the extent of items in the model. Each level represents a fixed number and then the extent of items can be easily converted in numbers.

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