# Calculating Divorce Rates

as part of its collaboration with the SERC Pedagogic Service.

#### Summary

*Unreviewed Activity submitted in preparation for the NNN Writing with Numbers Workshop*

This assignment acquaints students with a variety of ways to calculate the likelihood of divorce. Often the mass media and other reports tend to report divorce statistics in less useful and occasionally useless ways. Students use Excel to calculate and observe trends in divorce rates for national data from 1900 - 2004. From the data, students discuss which of three rates is the best way to measure divorce and write a short 2-3 page paper on their selection and the usefulness of three media related articles that discuss divorce rates.

## Learning Goals

## Context for Use

## Description and Teaching Materials

This assignment acquaints students with a variety of ways to calculate the likelihood of divorce. Often the mass media and other reports tend to report divorce statistics in less useful and occasionally useless ways. There are four ways to calculate divorce rates. The first, often called the "apples and oranges" method involves calculating a ratio of the number of divorces to marriages occurring in a given year. This involves comparing two groups which have little in common as only very few divorces involve marriages formed during the same year. The second, called the crude divorce rate, involves looking at the number of divorces taking place within the entire population whether married, widowed, too young to marry or not. These are the two most commonly used statistics in the media and in official governmental data.

The final two provide a more precise measure of divorce but are used less often. The refined divorce rate is based on the number of divorces within all marriages existing at a given time and is a useful way to look at the chances of divorce occurring. The last approach follows the amount of divorce occurring among a cohort of people who marry during the same year over time. This is a useful way to track when divorce occurs after marriage and to compare the likelihood of divorce within different cohorts.

In this exercise students calculate and graph the "apples and oranges," crude, and refined divorce rates from raw data from 1900 to the present in five and ten year intervals. They will be asked to discuss the advantages and disadvantages of each method. Finally, they will read examples of how all four rates are used in the media.

**Materials:**

- Correct spreadsheet (Excel 30kB May9 08)
- Assignment handout (Microsoft Word 14kB May9 08)
- Pre-test for divorce rates exercise (Microsoft Word 17kB May9 08)
- The Tricky Business of Estimating Divorce
- To Avoid Divorce ... ( 51kB May16 08)
- Blank spreadsheet for divorce (Excel 19kB May16 08)
- Divorce Rate: It's Not As High As You Think (HTML File 8kB May16 08)