Political parties certainly choose their candidates, as well as carry out the campaign in a way that best suits a particular political option in terms of being adequate to the political views of the party. They also design a political campaign platform and deal with technical issues such as finance for the implementation and design of the campaign itself. Political parties can also conduct a census, they do it, and use them in campaigns, but usually for a better effect, they use a census conducted by some agencies concerned so that the results of the census "look" more objectively. It has a greater impact on the population than when it presents the results of its own conducted census.
The answer is. conducting a census.