Epidemiological Tools

Epidemiological Tools
There are a variety of tools that an epidemiologist might have at his or her disposal. The most common tools that are used in the field are SAS, SPSS, EpiInfo, R, and many others. These require significant time and diligence to become proficient at each of these statistical tools. However, almost every office has Microsoft Excel, Numbers (the Mac equivalent), or Google’s Excel-like product.

Often times, epidemiological calculations can seem/appear intimidating. However, if you let the excel document do the work for you then you do not have to worry about making errors in simple math. Please download the attached Microsoft Excel spreadsheet. You will be doing the following:

Calculating:

Crude Mortality Rate
Age-Specific Mortality Rate
Age-Adjustment (using the direct method)
Prevalence
Incidence Density
Graphing:

Incidence and Prevalence
You will need to go to the Census Bureau, then click on Advanced Search then click on Geography. In the area marked state, county, or place, type your community or a community near you and select enter. You are going to want information from a table that contains Age and Sex in the title.

Please see attached file
To calculate the age-adjusted mortality rate using the direct method with your own population data, you will need to follow these steps:

Find the age distribution of your population: You can use the American FactFinder to find the age distribution of your population by selecting “Age and Sex” under “Topics” and then selecting your geographic area of interest. Make note of the population counts for each age group.

Calculate the expected deaths for each age group: To calculate the expected deaths for each age group, multiply the age-specific mortality rate (ASR) from the Example 2 chart by the corresponding population count for that age group in your population.

Calculate the sum of the expected deaths for all age groups: Add up the expected deaths for all age groups to get the total number of expected deaths.

Find the standard population: The standard population is typically the U.S. standard population, but it can be any population that you want to use for comparison purposes. You can find the population counts for the U.S. standard population on the CDC website.

Calculate the expected deaths for each age group in the standard population: Multiply the ASR from the Example 2 chart by the corresponding population count for that age group in the standard population.

Calculate the sum of the expected deaths for all age groups in the standard population: Add up the expected deaths for all age groups in the standard population to get the total number of expected deaths in the standard population.

Calculate the age-adjusted mortality rate: Divide the total number of expected deaths in your population by the total number of expected deaths in the standard population, and then multiply by 100,000.

Using the Example 2 chart with your own population data, the calculations would look like this:

Age Group Deaths Total Population ASR* Your Population Expected Deaths
0 – 14 4 231,158 0.000017304 25,000 0.4331
15 – 19 23 73,200 0.000314208 10,000 3.1421
20 – 34 500 231,158 0.002163023 40,000 86.5209
35 – 54 250 231,158 0.001081511 35,000 37.7534
55+ 1000 211,895 0.004719319 30,000 141.5796
Total 1777 978,569 269.4291

Standard Population: Using the 2010 US Census data, the standard population for the direct method is:

Age Group Population Count
0 – 4 19,175,798
5 – 9 20,139,890
10 – 14 20,614,728
15 – 19 21,562,957
20 – 24 22,654,708
25 – 29 22,932,629
30 – 34 21,108,314
35 – 39 19,550,529
40 – 44 20,012,262
45 – 49 19,629,740
50 – 54 18,786,902
55 – 59 16,978,131
60 – 64 14,281,953
65 – 69 11,413,225
70 – 74 8,638,512
75 – 79 6,181,138
80 – 84 4,137,979
85+ 5,325,868

Expected Deaths in the Standard Population:

Age Group ASR* Population