Calculating Odds Ratio
Data can be qualitative or quantitative. Qualitative data is helpful to generate a hypothesis and gather information if little is known about an expected association. Focus groups, key informant interviews, and case studies are types of qualitative data collection methods used to identify common themes from which to build a hypothesis. Quantitative data collection and analysis is used to test a hypothesis and make comparisons to determine the direction and strength of a potential association. The Behavioral Risk Factor Surveillance System (BRFSS) is cross-sectional panel survey used to collect quantitative data on adult behaviors and risk factors. It is one of the largest U.S. health data collection efforts. The data can be used to analyze associations on a state or country level. Follow the steps to obtain a 2×2 contingency table (also known as a “cross tabulation”) crossing binge drinking with depression.
1. Retrieve the “BRFSS Web-Enabled Analysis Tool” resource provided in the Topic Materials.
2. Select “Cross Tabulation.”
3. Select “2015” for the year.
4. Select “Arizona” for the state.
5. Select “Alcohol Consumption: Binge drinkers (males having five or more drinks on one occasion, females having four or more drinks on one occasion)” for Step 2 Select Row.
6. Select “Chronic Health Conditions: Ever diagnosed with a depressive disorder, including depression, major depression, dysthymia, or minor depression” for Step 3 Select Column.
7. Skip Steps 4 and 5.
8. Select “Sample Size” for Step 6 Select Statistics and run the report for the cross tabulation.
Using the data from the cross tabulation results, calculate the odds ratio for depression among those exposed to binge drinking. Interpret the odds ratio and discuss if the odds ratio is a good estimate of the relative risk in this situation. Why or why not? Show your 2×2 table and all calculations. Present or describe the formula you used to arrive at your answer.
Use the Topic Material, “BRFSS Web-Enabled Analysis Tool,” located on the CDC website, and run a report for two variables of interest to you. Create a 2×2 table and calculate the odds ratio for this association. Interpret the odds ratio and discuss the public health importance of the association. Show your 2×2 table. Present or describe the formula you used to arrive at your answer.