Understanding the difference between traditional, explanatory RCTs, PCTs, and quality improvement (QI) activities is important, because different ethical and regulatory guidelines may apply. RCTs and PCTs both constitute research, which is defined in federal regulations as an activity intended to create generalizable knowledge (45 Code of Federal Regulations (CFR) 46). Alternatively, QI activities have been defined as “data-guided activities designed to bring about immediate improvements in health care delivery in particular settings” (Lynn et al. 2007). When a PCT is intended to improve care locally and provide generalizable knowledge, as in a learning health system, the distinction between QI and research is arguably fuzzy (Faden et al. 2013), especially as QI techniques become more sophisticated and extensive (Finkelstein et al. 2015). At its core, however, QI is designed to change local processes to achieve accepted standards of care, while pragmatic research is designed to determine the standards themselves (Finkelstein et al. 2015). A single trial may also have some elements that are more pragmatic (e.g., a trial accepting all-comers with very limited exclusion criteria) and other elements that are more explanatory in nature (e.g., no flexibility allowed in how an intervention is delivered across settings) (Loudon et al. 2015). This is explored in more detail in the next section. The key differences between RCTs, PCTs, and QI activities are shown in the following Table. We explore the continuum of pragmatism in study design in more detail in the next section.

Key Differences Between Traditional RCTs, PCTs, and QI Activities