Margit Kooijman

Prognostic factors | 77 the number of studies evaluating this factor, consistency of results and methodological quality (Table 2). Results were considered consistent if > 75 % of the studies reported results in the same direction 9,10 . TABLE 2. Levels of evidence for prognostic factors on shoulder disorders Results Selection of studies The literature search yielded 5,004 citations. After completion of the selection procedure, 4,995 publications were eliminated based on title, abstract and full-text, leaving nine studies of which the methodological quality was assessed 11-19 . Figure 1 (flowchart) shows an overview of the study selection procedure. FIGURE 1. Overview of the selection procedure Level of evidence Strong Consistent findings (>75%) in at least two high quality cohorts Moderate Consistent findings (>75%) in one high quality cohort and at least one low quality cohort Weak Findings of one high quality cohort or consistent findings (>75%) in at least three or more low quality cohorts Inconclusive Inconsistent findings irrespective of study quality, or less than three low quality cohorts available No evidence No data presented