It is a common method of gathering information from a very specific group of individuals. It is a methodology where researcher recruits other individuals for the study. This method is used only when the population is very hard-to-reach. For example, these include populations such as working prostitutes, current heroin users, people with drug addicts, and etc. The key downside of a snowball sample is that it is not very representative of the population. Sampling can be a confusing activity for marketing managers carrying out research projects.
By knowing and understanding some basic information about the different types of sampling methods and designs, you can be aware of their advantages and disadvantages. The two main sampling methods probability sampling and non-probability sampling has their specific place in the research industry.
In the real research world, the official marketing and statistical agencies prefer probability-based samples. While it would always be good to perform a probability-based sampling, sometimes other factors have to be considered such as cost, time, and availability. Download the following Infographic in PDF. Silvia Vylcheva has more than 10 years of experience in the digital marketing world — which gave her a wide business acumen and the ability to identify and understand different customer needs.
What is a population? What is a sample? There are two basic types of sampling methods: Probability sampling Non-probability sampling. What is probability sampling?
Comparatively easier method of sampling Lesser degree of judgment High level of reliability of research findings High accuracy of sampling error estimation Can be done even by non-technical individuals The absence of both systematic and sampling bias.
Monotonous work Chances of selecting specific class of samples only Higher complexity Can be more expensive and time-consuming. What is non-probability sampling?
When a respondent refuses to participate, he may be replaced by another individual who wants to give information. If a researcher studied developmental milestones of preschool children and target licensed preschools to collect the data, the sampling frame would be all preschool aged children in those preschools. Students in those preschools could then be selected at random through a systematic method to participate in the study.
This does, however, lead to a discussion of biases in research. For example, low-income children may be less likely to be enrolled in preschool and therefore, may be excluded from the study.
Extra care has to be taken to control biases when determining sampling techniques. There are two main types of sampling: The difference between the two types is whether or not the sampling selection involves randomization. Randomization occurs when all members of the sampling frame have an equal opportunity of being selected for the study. Following is a discussion of probability and non-probability sampling and the different types of each.
Probability Sampling — Uses randomization and takes steps to ensure all members of a population have a chance of being selected. There are several variations on this type of sampling and following is a list of ways probability sampling may occur:. Non-probability Sampling — Does not rely on the use of randomization techniques to select members. This is typically done in studies where randomization is not possible in order to obtain a representative sample.
Bias is more of a concern with this type of sampling. The different types of non-probability sampling are as follows:. A Guide to Using Qualitative Research Methodology - The file linked below contains a full description of how to conduct qualitative sampling, including a chart that lists the types of sampling techniques and includes examples. Sampling Designs in Qualitative Research - The following article discusses sampling designs and ways to make the sampling process more public.
This pin will expire , on Change. This pin never expires. Select an expiration date. About Us Contact Us. Search Community Search Community. Qualitative Sampling Methods The following module describes common methods for collecting qualitative data. Describe common types of qualitative sampling methodology.
Explain the methods typically used in qualitative data collection. Describe how sample size is determined. Purposeful Sampling is the most common sampling strategy. In this type of sampling, participants are selected or sought after based on pre-selected criteria based on the research question. For example, the study may be attempting to collect data from lymphoma patients in a particular city or county. The sample size may be predetermined or based on theoretical saturation, which is the point at which the newly collected no longer provides additional insights.
Click on the following link for a desciption of types of purposeful sampling: Types of Purposeful Sampling.
Sampling Methods. Sampling and types of sampling methods commonly used in quantitative research are discussed in the following module. Learning Objectives: Define sampling and randomization. Explain probability and non-probability sampling and describes the different types of each.
Before sampling, the population is divided into characteristics of importance for the research. For example, by gender, social class, education level, religion, etc. Then the population is randomly sampled within each category or stratum.
Multistage Sampling (in which some of the methods above are combined in stages) Of the five methods listed above, students have the most trouble distinguishing between stratified sampling and cluster sampling. Types of Sampling Methods and Techniques in Research The main goal of any marketing or statistical research is to provide quality results that are a reliable basis for decision-making. That is why the different types of sampling methods and techniques have a crucial role in research .