Method for classifying test subjects in knowledge and functionality states

A method for classifying a test subject in one of a plurality of states in a domain, a domain being a set of facts, a quality measure having a range of values, or a combination of a set of facts and a quality measure, the set of facts for a knowledge domain being any set of facts, the set of facts for a functionality domain being a set of facts relating to the functionality of a test subject, a state being characterized by a subset of facts, a value in the range of values for a quality measure, or a combination of a subset of facts and a value for a quality measure, a first state being higher than or equal to a second state and a second state being lower than or equal to a first state if (1) the subset of facts or the quality measure value associated with the first state respectively includes the subset of facts or is greater than or equal to the quality measure value associated with the second state or (2) the subset of facts and the quality measure value associated with the first state respectively includes the subset of facts and is greater than or equal to the quality measure value associated with the second state, a test subject being classified in the highest state of which he has the knowledge or functionality, the method comprising the steps:

• specifying a domain comprising a plurality of states and determining the higher-lower-neither relationships for each state, the higher-lower-neither relationships for a state being a specification of which states are higher, which states are lower, and which states are neither higher or lower, the plurality of states including a first, second, and third fact state characterized by subsets of facts wherein (1) the first and second fact states are higher than the third fact state and the first fact state is neither higher nor lower than the second fact state or (2) the first fact state is higher than the second and third fact states and the second fact state is neither higher nor lower than the third fact state;
• specifying a test item pool comprising a plurality of test items, a test item engendering a response when administered to a test subject;
• specifying an initial state probability set (SPS) for the test subject to be classified, each member of the initial SPS being an initial estimate of the probability density value that the test subject is associated with a particular state in the domain;
• specifying a class conditional density f.sub.i (x.vertline.s) for each test item i in the test item pool for each state s in the domain, a class conditional density being a specification of the probability of a test subject in state s providing a response x to the test item i, each item partitioning the domain of states into a plurality of partitions according to the class conditional densities associated with the item, a partition being a subset of states for which the class conditional densities are the same or the union of such subsets;
• determining the classification of the test subject.