A critical review of scoring options for clinical measurement tools.

Maria Laura Avila,Jennifer Stinson,Leonardo R Brandão,Alex Kiss,Brian M Feldman,Elizabeth Uleryk

doi:10.1186/s13104-015-1561-6

Abstract

BackgroundThe aim of this paper is twofold: (1) to describe the fundamental differences between formative and reflective measurement models, and (2) to review the options proposed in the literature to obtain overall instrument summary scores, with a particular focus on formative models.MethodsAn extensive literature search was conducted using the following databases: MEDLINE, EMBASE, PsycINFO, CINAHL and ABI/INFORM, using “formative” and “reflective” as text words; relevant articles’ reference lists were hand searched.ResultsReflective models are most frequently scored by means of simple summation, which is consistent with the theory underlying these models. However, our review suggests that formative models might be better summarized using weighted combinations of indicators, since each indicator captures unique features of the underlying construct. For this purpose, indicator weights have been obtained using choice-based, statistical, researcher-based, and combined approaches.ConclusionWhereas simple summation is a theoretically justified scoring system for reflective measurement models, formative measures likely benefit from the use of weighted scores that preserve the contribution of each of the aspects of the construct.Electronic supplementary materialThe online version of this article (doi:10.1186/s13104-015-1561-6) contains supplementary material, which is available to authorized users.

Highlights

The aim of this paper is twofold: (1) to describe the fundamental differences between formative and reflective measurement models, and (2) to review the options proposed in the literature to obtain overall instrument summary scores, with a particular focus on formative models
The objective of this paper is to offer a brief summary of the fundaments of formative and reflective measurement models, and to review the different approaches used to obtain summary scores that have been proposed in the literature
According to classical test theory (CTT), the observed score (O), or test score obtained from a measurement instrument, comprises two parts: the true underlying score (T), which represents the hypothetical unobservable value that a subject has for a construct, and random error (E), which is the part of the observed score that can be attributed to measurement error [24]: O=T+E

Summary

Introduction

The aim of this paper is twofold: (1) to describe the fundamental differences between formative and reflective measurement models, and (2) to review the options proposed in the literature to obtain overall instrument summary scores, with a particular focus on formative models. From a holistic perspective [1], measurement has been described as an empirical process of “assigning numbers to objects or events according to a rule” [2] as well as an intellectual activity of “giving meaning to the theoretical variables”. A measurement model describes the relationship between a construct and its indicators [3]. Melancholia is a construct, and “depressed mood”, “tiredness”, and “sleep disturbance” are some of the indicators used to assess melancholia [5]. It has been stated that “the foundations of psychometric theory are full of theoretical tensions and fissures that mostly go unnoticed in the daily activity of test construction and use” [8]

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