What Is “Incidence Rate” and Why Does it Drive Research Costs? - (Archived)

One of the factors that can impact the cost of doing market research is the ease with which the research company can reach qualified respondents, and then encourage them to complete the survey. Quite simply, the harder it is to reach the target respondents, the more costly and time consuming the research project will be.

Of course, a vague answer like that is not helpful when a client is budgeting for research. Over the years, Market Connections (like other professional research firms) has developed ways to assess the required level of effort before the project starts. This helps us not only determine the most appropriate methodologies, but also to provide reasonably accurate project estimates and schedules. How we project the level of effort is through an estimated incidence rate.

Incidence Rate Defined

The textbook definition of incidence rate is the occurrence in the population of those who are eligible to complete a study. However, to better project study costs and gather more relevant data, Market Connections and our partners define incidence rate as the frequency of something occurring in a given population.

When we plan a market research project, one of the first things we do is estimate the number of people who, once we invite them to participate, will either not qualify for the survey (for example, because they aren’t involved in decision-making about the topic) or will decline to participate. If we believe five out of 10 people will qualify and complete the survey, the overall incidence rate is 50 percent. This estimate helps guide the cost of the project.

How the Source of the List Impacts Cost

The source and quality of the contact list has a significant impact on the incidence rate — the cleaner and better defined the list, the better it will be. For example, when conducting a customer satisfaction survey, our clients will provide a current customer list. Sure there may be a few bad phone numbers or incorrect email addresses, but we can be very sure the list is qualified. In that case, the incidence rate will be high and the cost per completed survey will be low.

How Target Audience Impacts Cost

How specific a targeted audience is will impact cost. For example, if you want to survey a very specific audience — only GS14s who make decisions regarding cybersecurity tools and have been in their position for more than 10 years — the incidence rate will be lower than if you simply want to reach government employees involved in implementing cybersecurity tools at all GS levels and tenure. In a nutshell, broader specifications equate to a lower level of effort in obtaining completed surveys, a higher incidence rate and a lower cost per completed survey. More stringent qualifications as noted in the first example above equate to a harder effort to obtain completed surveys, a lower incidence rate and a higher cost per completed survey. A difference of only 10 percentage points in incidence rate could easily translate to a 40 percent increase in fielding costs of the project.

How Past Experience Helps Determine Incidence Rate

Good research firms calculate the actual incidence rate for every study they complete. With that data it’s possible to compare incidence rates for past studies that have similarities to the one at hand.

Bringing it All Together

Other factors that impact incidence rate estimates include the data collection method (on-line, phone, or mail) and the length of the survey. Research pros can determine the required fielding resources, likely timing, and other project design elements to build a realistic research approach, budget and schedule. They will work with you to design the appropriate sample design with reasonable incidence rates that meet your budget requirements.


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