A Summary of Sampling
14 Apr 2023

After hours developing your research plan, writing your questions, and programming your survey, it is time to launch your survey. Before launching the study, it is essential to have a precise sample plan. This is a key step when fielding quantitative research. Proper sampling is important for making sure your research captures an accurate audience that your research is meant to represent. Here is a quick lesson on sampling, its importance, and how to properly plan your sample.

What is Sample? 

You have an audience you want to reach that is unique to your objectives. It may be the US population, students, buyers of gum, or even physicians. Regardless of who your audience is, it is not efficient to survey the whole population due to several factors, including price and logistics.  

That is where sampling comes in; it allows you to project the outcomes of a whole population based on a small subset. The larger the sample size, the smaller variance in error to match the population accurately. At a certain point, the variance becomes so small that increasing your sample size is no longer beneficial. 

You will need to take the following attributes into account to help determine the sample size: 

  • Size of your overall population
  • The margin of error (ideally, you want it to be less than 4%)
    • The degree of uncertainty 
  • Confidence level (typically, you base it on a 95% confidence level), 
    • The percentage of certainty that the confidence interval would contain the true population parameter when you draw a random sample.

When considering a sample size, you must understand whether you are sub-segmenting the audience or conducting advanced analytics. Both tactics may require more sample.

Representative Sample 

If your sample is supposed to match a particular audience in characteristics, then it is essential to make sure it is representative. This means proportionally matching characteristics such as demographic, purchase habits or behavioral attributes. For example, if your target population skews slightly more female, so should your sample.

Making your sample representative is important because it helps ensure that your data truly reflects your wider target audience. People from various backgrounds and demographics will have vastly different opinions. Therefore, making sure your sample includes the proper proportion of each of these individual differences helps keep your data accurate.

How Do You Ensure Your Sample is Representative? 

Proper representation is important, but how do you achieve it? There are a few ways to collect a representative sample, each with advantages and barriers. Choosing one of these methodologies can help prevent sampling error.

Stratified sampling

Stratified sampling involves specifying the needed cohorts within your sample and setting quotas for each. While specifically fielding for specific quotas, randomly selecting participants within these groups ensures unbiased data while still matching the sample to the population. The methodology provides high accuracy, but fielding the remaining open slots can become difficult and time-consuming as quotas fill.


Weighting achieves sample representation after survey fielding has already closed. The methodology involves adjusting the power of each respondent to make the influence of each sub-group representative of that population, even if the physical number of people in the sample is slightly off. 

Here is an example. Let’s say you have too few responses in your sample from people under 30 years old and too many people above 50. Weighting can make the answers from the younger group “worth more” than the answers from the older cohort. This evens the playing field when looking at the data.

Weighting can be an incredibly useful tool, allowing you to match the population even after responses have been collected. However, it is important to use the methodology sparingly, as over-weighting could provide too much power to an individual respondent, degrading the quality of your results. 

Combining stratified sampling with weighting

Using both methodologies to achieve proper representation can minimize the difficulties or challenges of using only one. Beginning with a stratified sample allows you to fill your survey with as much physical representation as possible. But when quotas start to fill up, and targeting becomes too narrow, minimal weighting allows you to stay on schedule by opening up to more general responses and making adjustments to correct the representation later on.

A One More Tip Before You Go…Use Databases

Often it can be difficult to pinpoint the demographic breaks for your sample. In these cases, there are several resources that you can turn to. The largest of these databases is the US Census. The Census collects countless data about the US population, from demographics to employment to homeownership. It is also free! 

Using the census and other databases to proportionally plan your sample will help ensure your research adequately reflects the larger population. Other databases, such as MRI, can provide attributes in regards to behavioral characteristics. However, many of the courses have a price tag. 


A well-planned sample will elevate your research and provide assurance that your analysis will be on-point, accurate, and statistically sound. If you don’t take the time to plan out your sample, you run the risk of degrading the quality of your data. It is crucial to take the time to gather the sample that fits your needs in order to set your analysis up for success.

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The Pros and Cons of Survey Intercepts
11 Apr 2023

Survey Intercepts! The methodology was popular before the growth of online research since all research was conducted offline or via telephone. However, survey intercepts are still useful and relevant today. This methodology involves stopping people on the street or in other public environments to interview them in person.

The method ensures high-quality responses and catches participants when memories are fresh. However, intercepts require intense planning and could incur high costs. Here are some pros and cons to help your company decide if this methodology suits your research needs.

The Pros of Survey Intercepts

Ensure that you are speaking to the right consumers

Ensuring the right people take your survey is essential to receiving quality results. What better way to meet your audience than on their turf?

Online surveys are a quick and convenient way to gather many responses. Still, several hours and quality checks must go into tailoring the survey to ensure only the proper respondents qualify for the study.

In-person survey intercepts can reduce errors by interviewing consumers at a time and place where you can be sure that they qualify. Whether your goal is to evaluate a restaurant experience or review a purchasing occasion, questioning the source in real-time will ensure you speak to the proper people for your study.

This methodology is excellent when you have niche locations where you want to find specific consumers. For example, a regional supermarket chain or a department store that wants to understand who is shopping at their establishment may use survey intercepts since being on-location will confirm that you are speaking to the correct shoppers.

Catch consumers at essential moments

The perks of survey intercepts extend beyond just ensuring you speak to the right audience. The methodology allows you to speak to them when their memories on the topic are fresh.

Distributing a questionnaire weeks or months after an experience or purchase, may change a visitor’s perception of the actual event. Intercepting visitors immediately after exiting an experience or an establishment will garner fresh thoughts that are not clouded by life events and responsibilities that have occurred in between.

Gather top-quality results without intense cleaning

Accurate surveys require reducing errors as much as possible. Unfortunately, the internet is not perfect, and errors occur. While some respondents will click through a survey without reading questions, others may not even be human! Online surveys must undergo an intense cleaning process to eliminate these participants. Results must be combed through for gibberish open-ends and straight-lined grids to eliminate lazy survey takers and bots.

When you survey a respondent in real-time, you can assess their engagement and ensure they answer the questions seriously and thoughtfully.

The Cons of Survey Intercepts

It is more difficult to gather a larger sample

Online studies through a panel or sample provider allow you to gather a large respondent pool, which gives more options for dissecting the data. More participants will allow you to break down respondents into more intricate sub-groups to see the differences between these segments. When your sample pool is more limited in numbers, some breaks may have too few responses to garner more than directional insights.

When you field a survey on-location, gathering enough participants to create substantial breaks can be a challenge, especially if you are in a low-traffic area. You become bound by the number of people visiting the location during the fielding period. Furthermore, only some people who show up will agree to participate. Online fielding may be a better option if your goal involves viewing the data through a lens of several subgroups.

A detailed plan of action is necessary

Fielding an online survey is simple. Pick your fielding panel, choose your target, and go! Survey intercepts?…not so much.

Many more steps of planning must go into the process.

  • First and foremost, you need people to conduct the intercepts.
  • You will also need a means of conducting the survey, such as tablets or computers.
  • If the survey is being built using an online tool, you’d better ensure the fielding location has stable internet.
  • Does the business have more than one location? If so, you need to properly field across multiple locations to ensure that there are no biases by focusing too much on one location.

You will also need to ensure you research any rules about the fielding location that can affect your project.

  • Are certain areas of the location off-limits?
  • Do you need a permit to conduct the research?
  • What are the times that the location is open?

If you decide to field your survey using this method, ensure all of these logistics are considered to avoid delays or, worse, have to cancel your study.

The cost can be high for a low number of responses

Fielding a survey online can be very cost-efficient. Depending on your target audience, you can complete a large study for as little as a few dollars per response. This is because people generally take online surveys when they have some downtime and have less on their minds.

When intercepting someone on the street to take a survey, they are likely on their way to another destination. They could be traveling to a meeting or event, or trying to catch a train. This unplanned participation makes the time you have with the participant more valuable, so incentives need to be more significant. Other costs include:

  • paying surveyors/interviewer
  • buying equipment
  • securing permits
  • paying for the researchers’ travel expenses

When added together, questioning a hundred people in person could cost the same, or more, as a thousand qualified respondents online!

How do you know if survey intercepts are right for you?

Choosing a methodology for research can take some careful thought and planning. Survey intercepts are integral in answering the questions you need in real-time from people you are certain just interacted with your brand. Their experience is fresh and their perceptions are top of mind, which can give a solid and accurate snapshot of their path to purchase. However, before green-lighting an intercept survey, here are some things all market researchers will need to consider :

  • Does this fit our budget?
  • Do we have the bandwidth and man hours to pull this off?
  • Is a smaller respondent pool enough to answer our objectives?

If you can check these boxes, a survey intercept could be the right methodology to gather the actionable insight you’ve been needing for your brand.

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