Item Reduction and Psychometric Validation of the Oily Skin Self Assessment Scale (OSSAS) and the Oily Skin Impact Scale (OSIS)

Abstract

Introduction

Developed using focus groups, the Oily Skin Self Assessment Scale (OSSAS) and Oily Skin Impact Scale (OSIS) are patient-reported outcome measures of oily facial skin.

Objective

The aim of this study was to finalize the item-scale structure of the instruments and perform psychometric validation in adults with self-reported oily facial skin.

Methods

The OSSAS and OSIS were administered to 202 adult subjects with oily facial skin in the United States. A subgroup of 152 subjects returned, 4 to 10 days later, for test–retest reliability evaluation.

Results

Of the 202 participants, 72.8% were female; 64.4% had self-reported nonsevere acne. Item reduction resulted in a 14-item OSSAS with Sensation (five items), Tactile (four items) and Visual (four items) domains, a single blotting item, and an overall oiliness item. The OSIS was reduced to two three-item domains assessing Annoyance and Self-Image. Confirmatory factor analysis supported the construct validity of the final item-scale structures. The OSSAS and OSIS scales had acceptable item convergent validity (item-scale correlations >0.40) and floor and ceiling effects ( 0.0001).

Conclusions

The OSSAS and OSIS versions tested in this study have been found to have strong psychometric properties in this patient sample (adults with self-reported oily facial skin), as assessments of self-reported oily facial skin severity and its emotional impact, respectively.

Authors

Robert Arbuckle Marci Clark Jane Harness Nicola Bonner Jane Scott Zoe Draelos Ronald Rizer Yating Yeh Kati Copley-Merriman

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