A Quick Guide to Understanding Comprehensive Surveys
Of all the many survey techniques available for understanding a business’s market, none is as powerful as the comprehensive survey. But what is a comprehensive survey and what does it actually entail?

In this quick guide, we’ll introduce you to everything you need to know about comprehensive surveys.

What is a comprehensive survey? 
A comprehensive survey is a survey that is done on an entire population. It is more popularly known as a census.

When you use a comprehensive survey, you distribute your questionnaire to all the members of a population. So, for example, if you want to know about the delivery and takeaway habits of Apartment Building A, you will need to make sure that everyone who resides in that building answers your questionnaire.

- Some examples of comprehensive surveys
Some of the most well-known comprehensive surveys include the following:

・National censuses done by countries, such as the Singapore Census of Population
・The UN World Population and Housing Census

However, not all comprehensive surveys need to be done on a large scale. Some populations that would be covered by a comprehensive survey include the following:

・Senior-year high school students in a private school to find out about their studying habits
・Employees of your business to check employee satisfaction

Comprehensive surveys vs survey sampling
Unlike comprehensive surveys, survey sampling studies do not need you to collect data from all members of the population. One example of this type is a study to find out about mobile trends in several countries, which does not need to collect data from the entire citizenry.

However, survey sampling studies are more prone to several research errors.

- Sampling error
A sampling error is a type of statistical error that occurs when the sample you choose does not represent the population you are researching.

Imagine this: you’re trying to find out the most popular infant formula brand purchased by a high-income household. However, you choose to get data from shoppers who buy infant formula in all the supermarkets in the area, regardless of whether they’re typically frequented by low-, middle-, or high-income households.

You can see that there is a high likelihood that the data you collect will not be representative of the population you are trying to research.

- Measurement error
A measurement error is a type of error that occurs when the recorded value differs from the true value.

In practice, this is what it looks like: let’s say that when you were researching that popular infant formula brand, one of the brands you listed was offering a huge discount that week. If you did not account for this in your questionnaire, then it is very possible that the responses you collected would not reflect the actual habits of the shoppers you surveyed.

This type of measurement error is called a systematic measurement error. There’s another type called random measurement error, which affects only a certain number of the people you surveyed.

Although these types of errors seem fatal, it is worth noting that there are statistical techniques that one can use to ensure that the data remain valid.

The benefits of a comprehensive survey
The largest benefits of comprehensive surveys for your business are as follows.

- Zero sampling error
Sampling error is always a major risk when doing a survey sampling study, and it can greatly affect your research result. This is a problem you don’t face when you use a comprehensive survey: the risk of sampling error completely disappears, since you collect data from the entire population.

- Surveys can be done on various segments
Although comprehensive surveys are more popular for large-scale research, they can also be done on smaller scales. Because of this, it’s very possible to get a thorough insight into a certain market segment, especially if you’re targeting a niche market.

The disadvantages of a comprehensive survey
The greatest disadvantage of a comprehensive survey is that it can be extremely costly, in terms of both time and money. And yes, this applies even to smaller-scale surveys, such as the example we described above.

Remember that when you choose to do this type of survey, all the members of the population have to answer the questionnaire.

Let’s go back to the example of Apartment Building A to get a better understanding. Imagine that you’ve successfully managed to get all the data from 1,000 residents of the building within one week. The problem is that the population of Apartment Building A is 1,003, so you’ll have to chase down the last three residents until you get their data, since you are, after all, doing a comprehensive survey.

Summary
A comprehensive survey is not always the most cost-effective or the most efficient, but it is one of the strongest market research tools out there. Depending on your business, it might be the best tool to get you the insight you need.