19.08.2015

Research sample selection key to valuable conclusions - ConQuest

Key information:

  • Market research is a key tool for companies and institutions around the world to obtain valuable information.
  • When dealing with a large population, a key stage of the study is the selection of the research sample.
  • The sampling process involves four basic steps: defining the target population, determining the sample size, selecting the sampling method and sampling the plan.
  • Sampling methods can be divided into two main categories: random (probabilistic) methods and non-random (non-probabilistic) methods.
  • Random methods give all individuals an equal chance to take part in the survey and include techniques such as simple random selection, stratified random selection, systematic random selection and cluster selection.
  • Non-random methods allow the interviewer to influence the selection of individuals, and selection techniques include purposive selection, random selection, quota selection and the snowball method.
  • The size of the research sample is a key element in research, enabling inferences about the population under study with sufficient accuracy and certainty.
  • There are various approaches to determining sample size, including arbitrary or subjective selection, analysis of the minimum number of observations needed for representation, consideration of budget constraints, and setting sample size based on a predetermined level of precision.
  • The choice of sampling method depends on the specifics of the study, the research objectives and available resources.
  • Adequate survey sampling ensures greater reliability and representativeness of the survey results, enabling valuable conclusions to be drawn.

Market research is one of the most popular methods of obtaining information used by companies and institutions around the world. Professional analysis can be a very valuable source of knowledge, and the subject matter of the survey itself is almost unlimited. Conducting such a survey seems easy when the target group is a few, a dozen or a few dozen individuals, but how to conduct a survey on a population of several hundred thousand? It would be almost impossible to conduct interviews with all residents of Wroclaw or to check the quality of each egg in a 300,000-egg shipment. The only fair solution in such a case is to select "representatives," i.e., a specific part of a given collective that will take part in the study.

More details below!

What is sampling?

What, then, makes it possible for us to analyze a study conducted on even a hundredth part of the population under study by reference to the whole, maintaining the reliability of the conclusions drawn? The key is the selection of the research sample. A properly selected research sample has a fundamental impact on the quality and credibility of the entire study. Sample selection is a key stage in the implementation of analyses and thus poses quite a challenge. In order to properly select a research sample, it is important to keep in mind the four basic steps of the process:

  • Defining the target population
  • Determine the sample size (this step has a direct bearing on the accuracy of our analysis - the larger the group of people who take part in the survey, the more accurate the results will be. Population size is an important factor in determining the minimum sample size and adequate sampling of population units).
  • Choice of sampling method
  • Sampling the plan

Research sampling methods

Sampling planning is a key process in research and marketing. It involves a number of steps, such as defining the target population, selecting the sampling method, determining the sample size, and ultimately collecting the appropriate samples.

The sampling method should be decided based on the type of information sought. Unfortunately, it is often determined by the availability of respondents. This process can be carried out according to two schemes.

The sampling method plays an important role in the sampling process. It is the way in which the units of the population under study are selected for sampling. There are various sampling methods, which can be divided into two main categories: random (probabilistic) methods and non-random (non-probabilistic) methods.

Both random sampling and non-probabilistic sampling techniques can be used to obtain a representative sample of the population. The choice of a particular sampling method depends on the research methodology adopted and the objectives of the study.

Depending on the requirements and objectives of the research project, a variety of sampling techniques are used that are tailored to the specific research context.

Random (probabilistic) testing

As the name suggests, this selection scheme involves the use of random sampling tools. The researcher has no influence on the selection process, and all individuals in the target group have an equal chance to participate in the study. As part of the randomized trial Several techniques are additionally distinguished.

The first is simple random selection. This is the easiest of the random methods and involves drawing the appropriate number of units from the population under study.

Another method is stratified random selection. The first step in this method is to characterize the structure of the population in terms of a certain characteristic or combination of them. Then draw an appropriate number of units from each stratum so that the sample structure agrees with the population structure.

Example:

If in a given population the number of smokers is 45% and the number of non-smokers is 55%, the researcher, taking into account addiction as a characteristic that shapes the population structure, should draw such a number of smokers and non-smokers that in the drawn sample they constitute 45% and 55%, respectively.

The third method is systematic random selection. It involves setting a certain frequency of drawing people from the population, for example, every tenth person in the study group will be selected.

Team selection, as another technique included in the random survey, is used in the absence of having a complete list of units of the analyzed population. It is necessary to draw teams (can be, for example, localities, institutions, schools) in order to obtain lists of their members, and then, based on them, a random selection is made.

Non-random (non-probabilistic) survey

Unlike the first scheme, non-random survey rejects the sampling procedure. It is also not fully independent, since the interviewer is given the opportunity to influence the selection of units, or more precisely, the mechanisms used.

One of the techniques non-random survey is purposive selection. It consists in selecting such units that are the source of the most valuable information on a given phenomenon.

Another technique is random selection. This method is based on the availability of the people interviewed. An example would be, for example, an interview on the street, when the interviewer quizzes people who happen to be within his reach.

The third method is quota selection. It is very similar to one of the methods of random sampling, since it too is based on describing the structure of the population under study in terms of a given characteristic or their combination, and then selecting such a number of people that the sample structure agrees with the structure of the population under study. The difference is the omission of the random sampling process. The researcher independently selects the people who will participate in the research.

There is another sampling method that is part of the non-random survey. It is a snowball method used when analyzing hard-to-reach communities. It involves reaching a small group of people exhibiting characteristics of interest, and then, through their acquaintances, reaching more people with similar characteristics.

Research sample size

Determining the sample size is a key element in research, enabling inferences about the population under study with sufficient accuracy and certainty. This is a complex process that requires knowledge of statistics and sampling theory. There are several approaches to determining sample size:

  • The first approach involves the analyst's arbitrary or subjective choice of sample size based on his or her own judgments.
  • The second approach is based on analysis and is determined by the minimum number of observations needed to obtain an adequate representation in the tier table.
  • The third approach takes into account budget constraints that may affect the sample size.
  • The fourth approach is based on determining the sample size based on a predetermined level of precision to be achieved in the survey.

Depending on the specifics of the survey and available resources, choosing the right approach to determining sample size is important to ensure reliable and representative survey results.

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    Diverse research sampling schemes: the key to valuable conclusions

    Sampling schemes and types of sampling are crucial when conducting market research. In the case of larger populations, where conducting a survey on the entire population is impossible, survey sampling becomes indispensable. There are various sampling methods, including among others. simple random sample, random sampling, and larger sample, which allow representative inference.

    In the case of a simple random sample, the units of the population under study are selected at random. This method gives all individuals an equal chance to take part in the study. Random sampling can also be implemented in a stratified manner, where the population is divided into layers due to a certain characteristic, and then an appropriate number of units are drawn from each layer. Another method is systematic random sampling, in which units are selected based on a fixed frequency of drawing.

    With a larger sample, sampling becomes more complicated, but gives greater representativeness of the population under study. Sample size is also an important factor to consider when selecting a sample. Depending on the size of the population, available resources and the level of precision, sampling should be calculated accordingly.

    It is important to understand that the selection of the research sample should be tailored to the specifics of the study, the research objectives and available resources. Properly conducted research sampling ensures greater reliability and representativeness of the survey results, enabling valuable conclusions to be drawn.

    Research sample selection: a key step in analysis and inference

    The sampling scheme is an important element in the research sampling process. It allows for the objective and random selection of population units for the study. Random sampling studies are often used to ensure that the results are representative. An example of random sampling can be simple sampling, where an appropriate number of units are drawn from the entire population. For larger samples, random sampling can be performed using advanced statistical techniques that take into account various parameters and characteristics of the population.

    Sample size is a key factor in selecting a research sample. The appropriate sample size has a significant impact on the accuracy and representativeness of the survey results. When selecting a sample size, it is important to consider the purpose of the survey, the resources available and the level of precision you want to achieve. In the case of non-random selection, where the interviewer has control over the selection of individuals, it is important to properly define the criteria and select the most valuable information regarding the phenomenon under study.

    Sampling allows a representative selection of the population units to be analyzed in the study. Stratified random sampling is one sampling method that divides the population into strata and then draws samples from each stratum. Random sampling is another method in which units are selected at random, ensuring a random selection process. Selecting a larger random sample can increase the precision of analysis and inference.

    Sampling - the right method

    Market research is an integral part of the functioning of most companies and institutions. It forms the basis of many important business decisions, so it is important that the conclusions drawn coincide with the truth as accurately as possible. Correct selection of the research sample, which is the key stage of any study, will certainly increase the reliability of the analysis and contribute to making the right decisions.

    Once we have a thorough understanding of the specifics of a survey, it remains to choose an appropriate sampling method. In the case of online surveys, many methods, especially non-random sampling, may seem unhelpful. However, the final choice is up to the interviewer, who makes the decision based on his preferences and research needs.

    The most commonly used methods are simple random selection and quota selection. The simple random selection method involves randomly selecting respondents from the entire survey population, while the quota selection method involves taking into account various population characteristics, such as age, gender or region, when selecting a sample.

    In the literature, one can also find a volunteer selection method. It involves leaving an announcement about the survey, to which willing respondents self-report their participation. In the case of online surveys, this method is very popular and is considered effective. However, it is worth noting that the representativeness of the sample selected in this way may raise some doubts.

    In conclusion, the selection of an appropriate sampling method for online research should take into account the specifics of the survey, the resources available and the purpose of the study to ensure the most reliable and representative results.

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