There are many different types of personality tests. The most common type is the self-report inventory which involves the administration of many questions to the ones who take the test. The answers are then evaluated vis-à-vis something that rates them and then evaluates their resultant behavior.
Sometimes those questions are not just plain questions but statements on which the test takers are evaluated. They are usually asked to respond having two-three options to choose from which evaluates their result according to the highest inkling towards which section. On terms of scoring, these personality tests can be evaluated using a dimensional, normative or a typological approach. Dimensional approaches describe personality as a set of continuous dimensions on which individuals differ.
Many psychological researchers believe that the dimensional approach is more accurate, although as judged by the popularity, typological approaches have substantial appeal as a self-development tool. There are times when emotive tests could in theory become prey to unreliable results due to people striving to pick the answer they feel the best fitting of an ideal character and therefore not their true response. In practice, however, most people do not significantly distort. But mostly people pick their true answer as they don’t know which the ideal answer is.
The meaning of personality test scores are difficult to interpret in a direct sense. Due to this, efforts are made by producers of personality tests to produce norms to provide a comparative basis for interpreting a respondent’s test scores. Common formats for these norms include percentile ranks, z scores, and other forms of standardized scores.
A substantial amount of research and thinking has gone into the topic of personality test development. Development of personality tests tends to be an iterative process in which a test is progressively refined. Test development can proceed on theoretical or statistical grounds. Theoretical strategies can involve taking psychological or other theory to define the content domain and then developing test items that should in principle measure the domain of interest.
This can then be accompanied by assessment by experts of the developed items to the defined construct. Statistical strategies are however varied. Common strategies involve the use of exploratory factor analysis and confirmatory factor analysis to verify that items that are proposed to group together into factors that actually do group together empirically. Reliability analysis and Item Response Theory are additional complimentary approaches.