When a resident completes a Zencity survey, they are asked for their zip code / postcode. That piece of information enables us to activate our geolocation process. One of the most valuable aspects of Zencity surveys, geolocation allows us to not only ensure that you are hearing from residents within your jurisdiction, it also allows you to view how satisfaction and attitudes differ across your community.

How does Zencity’s geolocation process work?

First, we verify that the zip code polygon or postcode indeed falls within your community. If it doesn’t, we exclude that submission from your satisfaction score calculation. 

When we are able to verify that a zip code or postcode does fall within your community, we automatically assign the submission to the most specific available region, from among the areas you defined with Zencity (e.g. neighborhood districts, counties, wards, zip codes, etc.).

Because zip code polygons often correspond to more than one region (postcodes are more localised), we use the population intersection percentage in the different regions to determine how to assign a location to a submission. More on that below.

How do we locate which subdivision a respondent is in?

To assign each respondent to an area, we use a geographic identifier that just about everyone knows: their home zipcode. We can then assign each response to a particular area.

Of course, ZIP codes rarely align with these geographic entities. To assign a person to an area, we use a probability model, based on the proportion of the ZIP code that overlaps with an area. For example, if 25% of ZIP code 90210 overlaps with Area A and 75% of that same ZIP code overlaps with Area B, a respondent in ZIP code 90210 has a 25% chance of being assigned to Area A and a 75% chance of being assigned to Area B.

This preserves differences on average. Although some respondents are not placed correctly, the errors balance out across a large enough sample, so the results for each area remain accurate. Think of it like flipping a weighted coin many times: even if any single flip could go either way, the overall outcome reliably reflects the true odds.

This approach also protects respondent confidentiality. Rather than asking residents for precise location details, the ZIP code a respondent shares is much more broad than a home address, which would more closely identify who is responding to the survey.

What happens if a submission can’t be geolocated?

If an invalid or no zip code / postcode is provided, we will be unable to geolocate that submission and it won’t be considered when calculating your score.

Summary of scenarios

The table below outlines the different possible scenarios that can occur when geolocating survey submissions, and how you can expect these submissions to be presented in your data as a result: