Estimating Incidence Rate
SurveyMonkey Audience allows you to buy survey responses for any survey you create on SurveyMonkey. You can target respondents based on specific attributes, like gender, age, income, employment status, and more to get answers from the people whose opinions you need.
If you need to find a specific group of people to take your survey and you can't find the exact attributes you need when creating your Audience collector, you can add one or more screening questions to your survey and apply logic to disqualify respondents.
Screening and disqualifying respondents is useful when you want to hear from specific types of people. For example:
- You want to find people who have shopped at a particular store in the last 30 days.
- You want to find Netflix subscribers who have watched one or more episodes of House of Cards.
- You want to find people who have purchased premium whiskey in the last 6 months.
Adding Disqualification Logic to Screening Questions
You can add one or more screening questions to your survey to make sure respondents meet the criteria you need for your project and disqualify respondents you aren't looking for.
- Add your desired screening questions to your survey design.
- Make sure to require the screening questions.
- Add Question Skip Logic or Page Skip Logic, depending which you need.
- When adding logic, choose to skip to a Disqualification Page.
When you're buying survey responses, you need to choose an incidence rate if you used disqualification logic in your survey.
The incidence rate is the percentage of respondents you think will qualify for your survey after answering your screening questions.
Choosing an Incidence Rate
The incidence rate you choose affects the number of people we send your survey to. For example, if you want 100 completed responses for your survey and you estimate an incidence rate of 50%, we’ll send the survey to up to 200 respondents.
If you're not sure what incidence rate to choose, it’s better to estimate a lower incidence rate (rather than higher) to help ensure you get all the completed responses you requested. If you estimate too high a rate, you may receive fewer completed responses than you need.
We're not able to help you choose the correct incidence rate for your survey—you are responsible for understanding how the incidence rate will affect your project.
How Incidence Rate Affects Your Project
To get the number of completed responses you ordered, we adjust the number of respondents we'll send your survey to based on your incidence rate.
- A high incidence rate indicates the type of respondents you're looking for are easy to find—a high percentage of respondents will qualify for your survey. Higher incidence rates cost less per response since we send your survey to fewer people.
- A low incidence rate indicates the type of respondents you're looking for are hard to find—a low percentage of respondents will qualify for your survey. Lower incidence rates cost more per response since we have to send your survey to more respondents to find enough people who qualify.
For example, if your incidence rate is 10%, it means that for 100 completed responses, we have to send your survey to 1,000 respondents in order to find enough people who qualify.
Estimated vs. Actual Incidence Rate
When you choose an incidence rate for your project, it's an estimated incidence rate. Your actual incidence rate is calculated for you as your results come in.
If you already have a project going, you can refer to your actual incidence rate in the collector. Go to the Collect Responses section of your survey and click the Targeted Audience Collector. The actual incidence rate is the number of respondents who qualified for the survey out of the total number of respondents who answered the screening questions.
If the actual incidence rate is higher than your estimate, your project should complete on time with the number of completes you ordered.
If the actual incidence rate is lower than your estimate, you may not get all the completed responses you ordered since more respondents will be disqualified from your survey. To collect more responses, you'll need to buy a new project using the actual incidence rate recorded for the survey.
Tips for Estimating Incidence Rate
While we're not able to help you choose the correct incidence rate for your survey, we have some tips we can share. Finding just the right people to survey has always been a challenge for market research, so if you don't know where to begin, don't worry—there are some techniques that people have developed to help estimate incidence rates.
Many companies already know roughly what to expect. For instance, a skiing equipment retailer may already have a rough idea of the income and age ranges of their customers, and roughly what percent of people in those demographics purchase skis. Try asking your colleagues if they know who would have access to data like this.
If you're targeting a well-known or well-researched population, there may be useful industry evidence documented online. For instance, if you are studying clothes dryers, a quick online search provides a study that shows roughly 85% of Americans own dryers. Therefore, 85% might be a good estimated incidence rate.
You can get a better idea (within a margin of error of +/- 10%) of the incidence rate for your screening questions by surveying just 100 people. This strategy works best if you plan on buying a larger sample and don't mind spending around $100 or so to get a better idea of what your incidence rate will be. Here's how:
1. Create a test survey
Create a short test survey containing the exact screening questions you'll be using in your survey.
Make sure to require the questions, but avoid using disqualification logic for this test.
The shorter the survey, the less expensive the project, so it's okay to only include the screening questions.
2. Launch a test project
Create a Targeted Audience Collector for the test survey and buy 100 survey responses.
Choose your targeting options carefully, as you'll want to use the exact same targeting options for your final project or the incidence rate won't be accurate.
3. See your incidence rate
Once your project is complete, go to the Collect Responses tab of your survey and open the Targeted Audience Collector containing your project summary. We'll outline your actual incidence rate and let you know exactly how many respondents qualified and how many didn't.
5. Launch the final project
Use the exact same screening questions that you used in your test survey in your final project. Even minor wording changes can greatly affect the incidence rate.
Make sure to require the screening questions and apply disqualification logic to them, as outlined at the top of this article.
Create a Targeted Audience Collector for the survey using the incidence rate you got for the test. Since the sample for the test survey was small, the actual incidence rate could be 10% higher or lower due to the margin of error, so we recommend you estimate 10% lower than the actual incidence rate for the test project just to be safe.