Validity, reliability, and neither.
Some studies of measuring instruments are validity studies. Others are reliability studies. Still others, such as the investigation of the stability of a construct and the correlation between the scores on two different levels of the same test, are neither. Authors of test manuals and of journal articles dealing with certain tests should label them accordingly as substantive studies, not methodological investigations.
D006801:Humans; D011581:Psychological Tests / Q000592:standards*; D011594:Psychometrics; D012107:Research Design / Q000592:standards*; D013223:Statistics as Topic