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Table 2 Items and criteria of the Newcastle-Ottawa scale for quality assessment

From: The impact of surgery-first approach on the oral health-related quality of life: a systematic review and meta-analysis

  Items When to give stars (low risk of bias)
Selection Representativeness of the exposed cohort truly or somewhat representative of the average in the community
Selection of the control group Drawn from the same community as the exposed cohort
Ascertainment of the treatment group Secure record or structured interview
Demonstration that outcome of interest was not present at start of study Yes
Comparability Comparability of participants on the basis of the design or analysis Study controls for the most important factor or any additional factor
Outcome Assessment of outcome Independent blind assessment or record linkage
Was follow-up long enough for outcomes to occur? Yes
Adequacy of follow-up Complete follow-up, or Subjects lost to follow-up unlikely to introduce bias, or small number lost follow-up, or description provided of those lost