Health economics is a broad field of science and contains different types of methods dependent upon the specific need. There is a growing interest in collecting data on medical service use and cost and effect of clinical trials. This could entail the cost of a drug, direct personnel cost, indirect cost of productivity loss of a patient, QALYs, reduced complications, mortality etc. Examples of elements of health economic analyses can be, an estimation of long-term survival and treatment effect of a new cancer drug, estimations of costs of interventions (e.g. micro-costing), simulation modelling, or other types of analyses. The most common analysis method is perhaps health economic evaluation. It is frequently used to evaluate interventions containing different drugs and the measurement of effect, but it is also increasingly used for trials of other medical therapies, such as surgical procedures or behavioural interventions. The steps involved in incorporating an economic evaluation alongside a randomised controlled trial include: quantification of the cost and effect of care, assessment of whether and by how much average cost and effect differ among the treatment groups, comparison of the magnitudes of differences in cost and effect and evaluation of the “value for the cost” of the therapies, for example by reporting incremental cost-effectiveness ratios (ICERs) and identifying the population to whom the results apply. To be able to conduct this, sound decisions need to be made about the length of follow-up, sample size and data collection.