<p> Economic evaluation and health technology assessment enable the comparison of different healthcare interventions, often through the calculations of incremental cost-effectiveness ratios (ICERs). Most studies that have found that using the societal perspective, which includes household and healthcare provider costs, results in lower ICERs than when the healthcare provider perspective is used. </p> <p> Household costs tend to be driven by the cost of productivity losses to patients and any caregivers. These costs will vary depending on whose time losses are included and how these are valued. For example, the commonly used friction cost approach only includes the amount of time needed for the employer to find a replacement the worker, excluding any time losses experienced by the worker after that. If average or minimum wages are used to value productivity losses by gender, this has the potential to exacerbate gender-based inequities with productivity losses in men being valued more highly than women. Furthermore, questions remain about whether time losses for populations who are not in paid employment should be captured. In some countries, informal workers are more common than formal workers, requiring specialised surveys to capture income losses, which fluctuate over time. </p> <p> This PhD project will explore resources for estimating the value associated with time losses, estimate the impact of different methodological approaches on the resulting ICER, and develop best practices for the inclusion of productivity losses in a range of settings. </p>