Researchers looked at whether planning sample sizes based on power analyses before a study leads to higher statistical power. They compared pre-registrations and IRB proposals that recommended power analyses with those that didn't. While more pre-registrations and IRB proposals included sample size decisions based on power analyses, this didn't result in larger planned sample sizes. The sample sizes determined in the pre-registrations and IRB proposals were not higher than those without guidance on sample size planning. Power analyses were often incomplete and didn't always relate to the main hypothesis test. There is room for improvement in the quality of registrations.