Randomization tutorial
Here is a brief tutorial on how to randomly select 30 communities from a list of 100 communities. The
same approach can be used to select households or anything else.
1. First, open the Community Randomization Spreadsheet in Excel:
2. Then, paste in the names of all the communities you wish to randomize. (Also paste in GPS
coordinates, if available).
3. Next, copy the randfunction cell once for each community you wish to randomize.
The randfunction is a function in Excel that generates a different random number between 0 and 1 every
time the function is used. The Excel formula for the randfunction is: “=Rand()”
To copy the randfunction for each cell you wish to randomize, select the randfunction cell along with the
and the 99 empty cells below it, then clicking: “Fill --> Down” at the top of the “Home” tab.
4. The randfunction cell should now be copied in all 100 cells; this gives you 100 different random
values.
5. However, these random values will change again each time you make any other changes in this
Excel sheet. We want to make copies of these values that will not change. To do this, select all
the randfunction cells and copy them.
6. Now paste the copied cells into the “random” column using the “paste values” function.
You now have 100 random values that will not change.
7. Now, select both the “random” column and your columns of community names and GPS
coordinates (if available). Go to the “Data” tab and select “Sort.”
8. Sort by “Random” from smallest to largest.
9. Now your communities are sorted in a random order (in order of the random numbers you
generated).
10. Select the desired number of communities from the top of the list (in this case it is the first 30
communities, because 30 is the number we wanted) and copy them (along with the GPS
coordinates, if available). Now paste these first 30 communities into the next tab on the
spreadsheet, called “Communities to monitor.”
11. Now we will select an extra 25-50% as alternates. Since we selected 30 communities to monitor,
let’s select an additional 15 alternates. To do this, select the next 15 communities from the
“Randomize” tab, after the 30 that we just selected, and copy these. Now paste these next 15
communities into the “Alternates” tab.
12. Our randomization is now complete. We have selected a random sample of 30 communities
from our original population of 100. In addition, we have selected an additional 15 alternate
communities, at random, which can be used if for some reason we are unable to monitor any of
our 30 selected communities.