A Mokken scale analysis of the Kessler-6 screening measure among Chinese older population: findings from a national survey

Zhongquan Li,Lisong Zhang

doi:10.1186/s12877-020-01771-w

Zhongquan Li, Lisong Zhang

Open Access

https://doi.org/10.1186/s12877-020-01771-w

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Abstract

BackgroundThe aging population increases rapidly across the world. Timely and effective screening of their mental-health problems is important to individuals, families, and the whole society. The Kessler-6 screening measure (K6) is a very popular instrument for non-specific psychological distress. However, few studies have focused on the psychometric properties of this instrument in the older population.MethodsThe present study employed Mokken scale analysis to evaluate its dimensionality and structure. This study also used differential item functioning (DIF) to examine whether the same structure existed across sex in a national representative sample of old Chinese people. Data were drawn from a public data set, the 2010 China Family Panel Studies (CFPS2010), and responses from a total of 6450 participants aged 60 years old and above (3136 males and 3314 females) were included in the final analysis.ResultsMokken scale analysis supported the unidimensional structure of the K6. Differential item functioning (DIF) analysis revealed that two of the six items (“Hopeless” and “Everything was an effort”) were marked for DIF based on the Chi-square. However, their impacts were negligible in terms of McFadden’s pseudo R2.ConclusionsThe K6 demonstrates adequate psychometric properties in the old Chinese population. The sum of all six items can be used as an indicator of non-specific psychological distress. Differences in the indicator across sex should be considered as a real difference in psychological distress between the female and the male.

Highlights

The aging population increases rapidly across the world
Reliability In addition to Cronbach’s α and Guttman’s lambda-2 λ2, we reported the Molenaar-Sijtsma (MS) reliability estimate and the Latent Class Reliability Coefficient (LCRC), which are recommended in the Mokken scale analysis
The present study employed a Mokken scale analysis on the Kessler-6 screening measure (K6) to evaluate its dimensionality and structure, and employed differential item functioning (DIF) analysis to examine whether the same structure existed across sex in a national representative sample of old Chinese people

Summary

Introduction

The aging population increases rapidly across the world. Timely and effective screening of their mental-health problems is important to individuals, families, and the whole society. The 6-item version of the Kessler Psychological Distress Scale (K6), a very brief instrument, has been developed to screen for non-specific psychological distress [5] It was initially designed for fast and accurate detection of severe mental illness among the general population. Due to its excellent performance and high efficiency, it is widely employed in several major global and national surveys, such as the WHO World Mental Health (WMH) Survey, the US National Health Interview Survey [6], the Australian National Survey of Mental Health and WellBeing [10], the Canadian National Population Health Survey [11], the South African Stress and Health study [12] It is included in the China Family Panel Studies (Institute of Social Science Survey, Peking University, 2015), a longitudinal survey of Chinese communities, families, and individuals

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