 # How to calculate the population of a specific year (for example 1974) with decennial census data of 1970 and 1980.

With decennial census data( population, for example 1970 and 1980) i would like to calculate the population of specific years (for example 1974). The dataset is in a panel structure where in the columns are the decennial census data and in the rows the cities (nhgiscode) and the years i would like to calculate the population for in a new variable. Is there a specific command (STATA preferred) i can use or some other possibilities?

As you can see in the image the population of ´70 and ´80 is given and i want to fill the variable popnew.

Thank you for your help!

kind regards

Nicolai Dear Nicolai,

The most straightforward way to create intercensal estimates is thru linear interpolation. You would subtract the pop70 value from pop80 (40165-20411 = 19574) in your example. Then I would divide the difference by 9 (19574 / 9 = 2174.9). I would then set the 1971 value equal to the pop70 + 2174.9. Finally, loop through all the years, adding 2174.9 to each prior year.

I don’t know the exact stata commands to execute this, but that is the basi algorithm.