Randomized experimental design yields the most accurate analysis of the effect of an intervention (e.g., a voter mobilization phone drive or a visit from a GOTV canvasser, on voter behavior).By randomly assigning subjects to be in the group that receives the treatment or to be in the control group, researchers can measure the effect of the mobilization method regardless of other factors that may make some people or groups more likely to participate in the political process.Individuals or groups may be randomly assigned to treatment or control groups.
This could be implemented by applying random assignment separately for male and female participants.
Random numbers make no guarantee that your control and treatment groups will be balanced in any way.
This is particularly true for small studies with few participants.
For example, perfectly valid random numbers could assign the 78 of the 100 heaviest participants in a weight loss study into the same group.
Information about the randomization procedure is included in each experiment summary on the site.
What are the advantages of randomized experimental designs?
The value of randomization may also be seen in the use of walk lists for door-to-door canvassers.
If canvassers choose which houses they will go to and which they will skip, they may choose houses that seem more inviting or they may choose houses that are placed closely together rather than those that are more spread out.
These differences could conceivably correlate with voter turnout.
Or if house numbers are chosen by selecting those on the first half of a ten page list, they may be clustered in neighborhoods that differ in important ways from neighborhoods in the second half of the list.