Looks at the generality and reliability of multi‐item measures that are based upon the perception of one or more individuals. Proposes that at least an overall time aspect is missing, which would contribute to the measurement of the perceived direction of change in a specific empirical context. The issues raised in current marketing research literature on the use of multi‐item measures relate to the generality and reliability of the findings regarding time and space. Emphasises the limits of the issues of time. The characteristics of data collected using a particular multi‐item measurement scale determine the reliability of the findings. Determines, by a methodological procedure, the generality of the empirical outcome. The results may lack reliability and generality over time even if the same items of measurement are used in the same context. Therefore, introduces an overall trend dimension in multi‐item measures in order to incorporate the time aspect for each dimension in a construct. The trend dimension makes it possible to measure the perceived direction of change, and complements the facets, as well as the perceptual degree, of a phenomenon or object in a specific empirical context.