Development and validation of sustainable employability index among older employees.

Background: Sustainable employability (SE) has become an important factor for keeping people in the labour market and enabling the extension of working life.

Aims: We developed and validated an SE index to predict assured workability in 2 years. Additionally, we developed a scoring tool to use in practice.

Methods: A questionnaire survey of postal employees aged ≥50 years was conducted in 2016 and followed up in 2018 (n = 1102). The data were divided into training and validation sets. The outcome was defined as whether the employees had an assured workability after 2 years or not. Multivariable log-binomial regression was used to calculate the SE index. The area under the curve (AUC) was calculated to assess the discriminative power of the index.

Results: The probability of assured workability increased with increasing quintiles of the SE index. The highest quintiles of the SE index showed the highest observed and expected assured workability in 2 years. The predictive ability, area under the curve (AUC) for training was 0.79 (95% CI 0.75-0.83) and for validation data was 0.76 (95% CI 0.73-0.80). In the scoring tool, the self-rated health, workability, job satisfaction and perceived employment had the highest contribution to the index.

Conclusions: The SE index was able to distinguish the employees based on whether they had assured workability after 2 years. The scoring method could be used to calculate the potentiality of future employability among late midlife postal employees.