Market research couldn’t be carried out without sampling because it isn’t possible to access every current or future customer. Market researchers rely on a variety of methods and sampling techniques to capture as wide a range as possible the many types of customers a client hopes to get insight into. Don’t confuse sampling with polling, they are two different things. More often than not, sampling is used for market research studies, not polling.
Qualitative research consultants work closely with their clients to understand their objectives and will create sampling groups based on this feedback. The quality of the research is largely driven by the quality of the sampling methods which is why it’s best to hire nationwide qualitative research firms, rather than try and do this “in-house”. Knowing which type of sampling technique to use is important so that data aren’t skewed or biased.
The two main types of sampling methodologies are probability and non-probability.
Probability, or random, sampling methods include all members of a target population and isn’t burdened by prior events in the selection process. Looked at another way, selecting individuals for a sample group doesn’t affect the chance of anyone else in the targeted population to be selected. So how do market research recruiting firms select people to be included in a study? Researchers and recruiters rely on four types of commonly used techniques including: Systematic Sampling, Simple Random Sampling, Stratified Sampling, and Cluster Sampling.
Systematic Sampling—Rather than randomly select individuals within a population, this method “systematically samples” by selecting participants. An example would be a market researcher selecting every 15th person from a list of the population. Systematic sampling does allow for a controlled way to select from a target population; however, it may be skewed depending on how the original list is organized or structured.
Simple Random Sampling—This is the most commonly used sampling technique, and is truly random. This method will randomly select individuals from a list of the population, and every individual has an equal chance of being selected.
Stratified Sampling—This method is an amalgamation of Systematic Sampling and Simple Random and is most often used when there are a multitude of distinct subgroups that require full and randomized representation across a sampling population.
Cluster Sampling—Cluster sampling is a variant of Simple Random Sampling and is typically used with larger populations and across broader geographic regions. It’s not uncommon for a population to be segregated into clusters and then randomly selecting participants from these groups.
Non-probability sampling methods aren’t as commonly used and often contain sampling biases. While they’re not as ideal as probability sampling methods, sometimes it is the only option given budget restraints, or lack of access to a full population list. If a qualitative research consultant has not choice but to go with a non-probability sampling method, s/he must be careful when drawing conclusions because the population is not randomized and biases inherent.
Most organizations hoping to learn more about their target populations know that hiring nationwide qualitative research firms with experience selecting sampling populations based on the above-outlined methodologies is money well spent.