In developed countries, population is aging, demand for primary health care (PHC) rising, and shortage of healthcare professionals growing. Increased cost-sharing can ease this challenge, yielding more revenue to finance the services and most likely reducing healthcare expenditure in the short term by decreasing service use. However, increased cost-sharing may have negative side effects on inequality as low-income individuals may face a higher barrier to access. It could also worsen population health, if missed visits lead to unmet health needs.

This doctoral thesis studies empirically whether moderate copayments in Finnish public PHC causally affect the use of PHC services and whether low-income individuals respond more strongly to copayments than the rest. The thesis consists of four coauthored essays that are based on comprehensive Finnish administrative register data.

The first essay analyzes the effects of introducing a 10-euro copayment for nurse visits on PHC use of adults in 2014–2019. Nurses increasingly examine and treat primary care patients, but there is little evidence on the impacts of cost-sharing for nurse visits. We fill this gap by using a staggered difference-in-differences (DID) design and state-of-the-art estimators. Our results show that the copayment reduced nurse visits by 9–12% during a one-year follow-up. We find heterogeneity by income in absolute terms, but not in relative terms. Thus, the resulting barrier to access may have been higher for low-income households. The effects on general practitioner (GP) use were negative but small, and statistical significance varies depending on the specification. Unlike much of the earlier Nordic literature, we estimate the effects for the whole adult population and not just for adolescents at a specific birthday. We also use a detailed pre-analysis plan (PAP), which has been rare in nonexperimental economics.

The second essay examines the impacts of copayments of 14–21 euros on GP visits at the 18th birthday, when previously exempted adolescents become subject to copayments in many municipalities. The study uses an age-based regression discontinuity (RD) design and variation across municipalities in whether the copayment changes discontinuously at the 18th birthday (RD-DID). We find that GP visits decreased by 4–5% in the copayment municipalities relative to the comparison municipalities at the 18th birthday. The reductions were largest for the bottom 20% of the equivalized family disposable income distribution, but surprisingly also larger than average for the top 50%. Compared to earlier related Nordic studies, our effect estimates are smaller and the heterogeneity by income level is weaker. We contribute by combining recent data from 2011–2019 with a design that also has comparison areas and by using state-of-the-art methods for RD designs with a discrete running variable.

The third essay analyzes whether abolishing a 14-euro copayment for GP visits in Helsinki, the capital, increased the number of GP visits among adults. Using a DID design and data from 2011–2014, we find that the abolition was associated with only a small increase in GP visits (+0.04 visits annually, or +4.4%, for all adults). The increase was driven by low-income adults (+0.06 visits, or +4.5%, at the bottom 40%). The setting is challenging for inference due to only one treated cluster and a finite number of comparison clusters. Although our point estimates are rather robustly positive, conclusions regarding the statistical significance are sensitive to how we account for clustering.

The fourth essay reports the results of a randomized controlled trial that examines the effectiveness of an informational campaign that reminded citizens aged 55 and above about the importance of early detection and treatment of health conditions. The campaign, which took place during the second year of the COVID-19 pandemic, also informed of a policy change that abolished the copayment for nurse visits in PHC. We found no evidence of either the intervention in general or the information on the copayment abolition having increased PHC utilization. Furthermore, we found no evidence of treatment effect heterogeneity. These findings suggest that informational outreach programs may not be effective in inducing curative PHC visits in a gatekeeping system. They are also a healthy reminder that not all nudges always work.

The thesis essays and our related policy report (in Finnish) make an important contribution to national policy discussions. The Finnish setting is characterized by moderate copayments, gatekeeping, and relatively tight supply. Our findings suggest that copayments have a moderate or small effect on PHC utilization in Finland. Copayments also seem to have non-trivial effects on inequality as low-income individuals respond more strongly in terms of visits, although we do not find such heterogeneity in relative terms. Besides these results, the thesis contributes by advancing the use of good research practices, such as the sharing of all replication codes and the use of detailed pre-analysis plans. I believe that both practices should be adopted much more widely, especially by researchers evaluating the impacts of public policies.