(How) should we measure sleep discrepancy?

Sleep discrepancy, the discordance between self-report and objective measures of sleep, is a crucial to understanding insomnia and sleep measurement. This thesis takes a conceptual and methodological perspective to sleep discrepancy. First, a scoping review clarifies sleep discrepancy concepts and identifies methodological problems. Next, one of these problems, the use of derived indices, is explored in detail within a methods-oriented paper and solutions are proposed. An empirical study then applies a proposed solution, providing novel insights into the relationship between sleep discrepancy and insomnia. A final chapter integrates findings into contemporary theory for insomnia.