The unit effect from a performance management perspective

Purpose - The subjective interpretation of numerical information can induce the so-called unit effect, i.e. the scale and unit chosen to quantify such information might influence a person's judgment. Although this bias is well-known, until now, it has been difficult to obtain an overview of the respective research. There are a variety of versions of the unit effect, different terms are used for the same kind of effect and proposals for grouping such effects lack a straightforward typology. Design/methodology/approach - A literature review is conducted using a systematic literature search design. We address the following questions: (1) What knowledge exists about the unit effect? (2) What is a suitable concept for structuring the findings? (3) What ideas can be deduced for future research focusing on performance management? Findings - A total of 11 versions of the unit effect and 27 moderating variables are identified and grouped into four contexts in which the effects occur. Structured according to these contexts, research ideas are depicted. They include suggestions for studies adapted to the field of performance management to scrutinize the main effects and moderators addressed in the literature to date as well as to consider additional potential moderators. Originality/value - Few publications explicitly address the unit effect from the perspective of performance management. As one of the core objectives of this business function is to enable rational decision-making based on numerical information, it can be assumed that corresponding research will be very fruitful.