1- , asgharimo@tbzmed.ac.ir
Abstract: (10819 Views)
The P-Value cannot present a complete measure of association in medical studies considering the
association between categorical variables. In such situations, measures are required to reveal the
clinical importance of relation along with their statistical significance, as the effect size. This paper
aims to introduce the measures of associations for categorical variables and inferences about them in
these studies. Principles and method of calculating measures of associations and inference about them
including confidence interval and hypothesis testing were presented to assess the relationship between
qualitative variables for all types of medical studies taking into account relevant considerations.
Additionaly, the method of reporting of findings were introduced in the context of contingency tables.
To investigate the relationship between two binary qualitative variables, should be used the Odds
Ratio in cross-sectional or case-control studies, the relative risk in cohort studies, and prevalence ratio
in cross-sectional studies and risk difference in all type of studies along with their confidence intervals
and/or their significance tests considering the independent or related groups of studies. Additionally,
for bigger than 2 by 2 tables, the method of calculating of above mentioned measures considering a
reference category and other measures such as Phi, Crammers V, contingency and uncertainty
coefficients , Lambda, Gamma, Summers D, Kendals tau-b and tau-c would be recommended. In each
of these situations, based on research based examples, calculations of tests were performed and their
results were presented. To investigate the relationship between a set of risk factors and binary and
multi-category qualitative variables, the introduced analyses are recommended considering the
situation and purpose of the proposed study.
Type of Study:
Research |
Subject:
General Received: 2014/07/12 | Accepted: 2014/07/12 | Published: 2014/07/12