“…The SCI has subsequently been translated, and validated further in Italian, Romanian, Chinese and French (Bayard et al ., ; Palagini et al ., ; Voinescu and Szentagotai, ; Wong et al ., ). The SCI has demonstrated sound psychometric properties previously, including internal consistency (published range: α = 0.71–0.89), convergent validity with the Pittsburgh Sleep Quality Index ( r = 0.73) and the Insomnia Severity Index ( r = 0.79), predictive validity in relation to insomnia disorder when diagnosed by expert clinical interview (Bayard et al ., ; Palagini et al ., ; Wong et al ., ) and has proved sensitive to change in several clinical trials (Barnes et al ., ; Bostock et al ., ; Espie et al ., ; McGrath et al ., ). Secondly, we will present sex‐ and age‐referent data on a sample of 200 000 people to facilitate the use in clinical and research settings.…”