These two research methodologies, quantitative and qualitative, generally polarize along the objective (quantitative) and subjective (qualitative) continuum, yet Park and Ernst's study has aspects of both.
They summarize their study as "a systematic review of all randomized controlled trials (RCTs) on the effectiveness of Ayurvedic medicine for RA." Thus, it is qualitative in nature. However, their research design and meticulous literature search are consistent with quantitative studies - structured, repeatable, well documented and theory based.
The integrity of a literature study depends on the integrity of trial selection. Biased trial selection can bias the study. The authors took noteworthy precautions to ensure the study's integrity. They found only seven RCTs meeting their inclusion criteria:
After their comprehensive search, the authors indicate they identified 33 trials. This is a satisfactory sample size, but their review revealed trials with methodological concerns, particularly non-randomization, observational structures, or lacking controls. ...