Size effect in observational studies in Public Oral Health: importance, calculation and interpretation

Abstract

The objective of this study was to analyze the scientific literature in public oral health regarding calculation, presentation, and discussion of the effect size in observational studies. The scientific literature (2015 to 2019) was analyzed regarding: a) general information (journal and guidelines to authors, number of variables and outcomes), b) objective and consistency with sample calculation presentation; c) effect size (presentation, measure used and consistency with data discussion and conclusion). A total of 123 articles from 66 journals were analyzed. Most articles analyzed presented a single outcome (74%) and did not mention sample size calculation (69.9%). Among those who did, 70.3% showed consistency between sample calculation used and the objective. Only 3.3% of articles mentioned the term effect size and 24.4% did not consider that in the discussion of results, despite showing effect size calculation. Logistic regression was the most commonly used statistical methodology (98.4%) and Odds Ratio was the most commonly used effect size measure (94.3%), although it was not cited and discussed as an effect size measure in most studies (96.7%). It could be concluded that most researchers restrict the discussion of their results only to the statistical significance found in associations under study.

Análise do componente genético do Diabetes Mellitus tipo 2

“…pelo autor.𝑅𝑎𝑧ã𝑜 𝑑𝑒 𝐶𝑎𝑠𝑜𝑠 𝐸𝑥𝑝𝑜𝑠𝑡𝑜𝑠 = 𝑁ú𝑚𝑒𝑟𝑜 𝑑𝑒 𝐶𝑎𝑠𝑜𝑠 𝐸𝑥𝑝𝑜𝑠𝑡𝑜𝑠 (𝐴) 𝑁ú𝑚𝑒𝑟𝑜 𝑑𝑒 𝐶𝑎𝑠𝑜𝑠 𝑁ã𝑜 𝐸𝑥𝑝𝑜𝑠𝑡𝑜𝑠 (𝐶) 𝑅𝑎𝑧ã𝑜 𝑑𝑒 𝐶𝑜𝑛𝑡𝑟𝑜𝑙𝑒𝑠 𝐸𝑥𝑝𝑜𝑠𝑡𝑜𝑠 = 𝑁ú𝑚𝑒𝑟𝑜 𝑑𝑒 𝐶𝑜𝑛𝑡𝑟𝑜𝑙𝑒𝑠 𝐸𝑥𝑝𝑜𝑠𝑡𝑜𝑠 (𝐵) 𝑁ú𝑚𝑒𝑟𝑜 𝑑𝑒 𝐶𝑜𝑛𝑡𝑟𝑜𝑙𝑒𝑠 𝑁ã𝑜 𝐸𝑥𝑝𝑜𝑠𝑡𝑜𝑠 (𝐷) OR mede quão fortemente um evento está associado à exposição, indicando a proporção de dois grupos de chances: as chances de o evento ocorrer em um grupo exposto e as chances de o evento ocorrer em um grupo não exposto. É o índice de tamanho de efeito mais utilizado para demonstrar aumento ou diminuição na chance de uma doença em estudos epidemiológicos, por exemplo(137).…”