5. Analytical studies

  1. A. Gouveia Oliveira

Published Online: 12 JUL 2013

DOI: 10.1002/9781118670767.ch05

Biostatistics Decoded

Biostatistics Decoded

How to Cite

Oliveira, A. G. (ed) (2013) Analytical studies, in Biostatistics Decoded, John Wiley & Sons, Ltd, Chichester, UK. doi: 10.1002/9781118670767.ch05

Editor Information

  1. Department of Pharmacy, Universidade Federal do Rio Grande do Norte, Natal, RN, Brazil

Publication History

  1. Published Online: 12 JUL 2013
  2. Published Print: 3 SEP 2013

ISBN Information

Print ISBN: 9781119953371

Online ISBN: 9781118670767



  • analytical studies;
  • association;
  • attributable risk;
  • non-probability sampling;
  • odds ratio;
  • population means;
  • population proportions;
  • relative risks


Descriptive studies are an essential instrument to document in detail the various features of the condition being studied. To describe and understand a given clinical condition one may be interested in exploring associations between variables. It is generally accepted that, although the means and proportions of attributes may vary among different segments of a population, the direction and strength of an association between variables does not vary greatly. The ratio of two proportions, called the risk ratio or, more commonly, the relative risk, is extensively used in epidemiology as a measure of association. When one identifies an association between a disease and a factor, relative risks and odds ratios answer the question of how much that factor increases the likelihood of disease. Shortcut formulas give us a simplified way to find attributable risks from relative risks and odds ratios, which is adequate for mental calculations.