Designer testing: using subjects' personal vocabulary to produce individualised tests

The principle of designer tests is that of using a subject's own semantics rather than lists of words that may or may not be relevant or even understandable for the subject. The Personalised Emotional Index (PEI) is a prototype designer test, in this case a mood test, that uses words that the subject chooses from a list of suggestions within mood categories. Each person's test is custom made from familiar and understandable words from his/her own vocabulary. Such a test has much face validity, can be succinct and has comprehensibility for the subject. The results obtained when using this test at the same time as the Profile of Mood States Bipolar Version (POMS-BI) were very similar (e.g. in a regression analysis, the ‘elated-depressed' variable predicted present overall mood on both tests (POMS: t=5.25, p<0.000, PEI: t=5.84, p<0.000) with a high correlation for total scores (r=0.82, p<0.000). The PEI results were correlated within the two week interval (r's about −0.74; p<0.000) and reasonably but not highly correlated on retesting some months after the first testing (r's about −0.25; p<0.000). It was successfully used to differentiate mood variables from a group consisting of caregivers of people with schizophrenia (n=30, producing 399 days of data) and a group of unselected controls (n=62, producing 1080 days of data). The test appears to have validity, reliability, comparability, and utility.