Before revision: Study designs used Randomized control trials Cross-sectional studies cohort studies Meta-analysis Systematic reviews Planned Experimentation (QI Research method) Difficulties Fragmentation of outcomes research: Databases and patient registries are fragmented and limited in the number of patients, and many are of unknown data quality.
After revision: Study designs used Randomized control trials Cross-sectional studies cohort studies Meta-analysis Systematic reviews Difficulties Fragmentation of outcomes research: Databases and patient registries are fragmented and limited in the number of patients, and many are of unknown data quality.