Platinum Priority – Editorial Referring to the article published on pp. 579–585 of this issue Maintenance Bacillus Calmette-Guérin: Why Is There Continued Debate?

The goal of scientific research is to arrive at a reasonable estimate of the truth with respect to some underlying question of importance. In clinical medical research, multiple types of study designs help point investigators toward the truth, including cross-sectional studies, case-control studies, cohort studies, clinical trials, and meta-analyses. Methodologists and proponents of evi-dence-based medicine have argued that there exists a pyramidal hierarchy of study designs, suggesting that certain study designs more closely approximate the truth than others [1]. Randomized trials (and meta-analyses thereof) are generally allotted the highest rank on the pyramid, whereas observational studies are relegated to lower ranks. However, little evidence supports the concept of a hierarchy of study designs, and several thoughtful analyse