Organizing Epidemiologic Data Importance of Data Organization Makes

Organizing Epidemiologic Data

Importance of Data Organization • • • Makes large data sets manageable Allows for analysis Relationships between disease and exposure Trends Communication

Tables • Arranged in rows and columns • Can show patterns, trends, relationships or differences • Simplicity • Self-explanatory

One-Variable Table • Frequency Distribution • 1 st Column shows category – Sex = Male or Female • 2 nd Column shows Number in each category • Can have additional columns – Percent – Cumulative percent

Highest No of cases

Intervention?

Who to target?

Two- and Three-Variable Tables • • More in depth analysis Be careful not to get to complicated Look for associations 3 rd variable allows for stratification

Use of Two-By-Two Tables • Calculate association between disease and exposure Ill Well Exposed a b Unexposed c d Total N ad/bc = Odd Ratio Relative Risk

Odd Ratio = 100 x 2340/89 x 811 = 234000/72179 OR = 3. 24 Exercise 4. 1 B on page 212

Answer to 4. 1 B OR = 12 x 17/2 x 5 = 204/10 OR = 20. 4

Class intervals • May want to group data • Split variables into Categories – Age • Continuous (1, 2, 3, etc…. ) • Categorical (<1, 1 -5, 6 -10, etc…. ) • Watch out for overlap

La. Crosse Age Groups

Graphs/Charts • • Shows data visually Patterns, trends similarities and differences Audience remembers Many types – Line – Histogram – Bar – Pie

Mapping • Use of Coordinates • Shows geographic location/distribution • Can be important in – Outbreak investigation – Health assessments – Intervention planning/evaluation

Mapping in Rabies Control • • • Background on raccoon strain rabies in WV Oral Rabies Vaccine Project (ORV) Active Surveillance Rabies Coordinates Establishing the ORV barrier

Benefits of Organizing Data • • • Summarizes large data sets Displays Analysis Visual representation of trends Education Funds Increase knowledge