Internet gaming disorder as a formative construct : implications for conceptualization and measurement

Background. Some people have serious problems controlling their internet and video game use. The DSM-5 now includes a proposal for ‘Internet Gaming Disorder’ as a condition in need of further study. Various studies aim to validate the proposed diagnostic criteria for Internet Gaming Disorder and multiple new scales have been introduced that cover the suggested criteria. Approach. Using a structured approach, we demonstrate that Internet Gaming Disorder might be better interpreted as a formative construct, as opposed to the current practice of conceptualizing it as a reflective construct. Incorrectly approaching a formative construct as a reflective one causes serious problems in scale development including (a) incorrect reliance on item-to-total scale correlation to exclude items and incorrectly relying on indices of inter-item reliability that do not fit the measurement model (e.g., Cronbach’s α) (b) incorrect interpretation of composite or mean scores that assume all items are equal in contributing value to a sum score, and (c) biased estimation of model parameters in statistical models. Implications. We show that these issues are impacting current validation efforts through two recent examples. A reinterpretation of Internet Gaming Disorder as a formative construct has broad consequences for current validation efforts and provides opportunities to reanalyze existing data. We discuss three broad implications for current research: (1) Composite latent constructs should be defined and used in models, (2) Item exclusion and selection should not rely on item-to-total scale correlations, and (3) Existing definitions of Internet Gaming Disorder should be enriched further