Sunday, January 24, 2010

How to Determine Birth and Growth Rate

Geographers doing demography are frequently required to determine what the birth rate for a subject area is. Surprisingly, however, I have discovered that many students are not taught how to find out crude birth rate. Fortunately it is real simple and I will explain it below

  1. Take the total number of births divide by the population of the subject area during the mid-year (If you cannot get that number just take the average of the population between the next year and previous year).
  2. Take the new number (births/mid-year population) times 1000. This will give the birth rate in terms of births per 1,000 people.

For example, if there are 3,467 births in a province of 93,987 people then the birth rate would be calculated as "(3467/93987)*1000" which equals 36.89 births per thousand people.

For growth rate the formula is real similar. Just take the new population and subtract the previous year's population. Take that number divided by the old population to determine the rate in a percentage.

For example, if there are 4,572 people in a town in 2008 and 4,687 people in the same town in 2009: take "(4687-4572)/4572" to equal 0.02515. Times the answer by 100 to get a percentage and the growth rate is 2.515% a year.

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