Question

Is sampling always necessary? Discuss under what circumstances it is necessary and under what circumstances it would not be.

Answer 1

Sampling is one of the most important factors for any research is going to be conducted, irrespective of the field of research. Be it psychology, sociology, etc.

In any kind of study, there is a target population which might be all humans and in some cases, the population might be restricted to a specific group of people (or a target).

Unless your study is going to be very generic which does not include gathering data from a target group, from the population they belong to, you won’t need sampling. But in cases where research-oriented data gathering is involving, sampling is a crucial step.

Circumstances where sampling is used:

1. Psychological Researches
2. Medical researches
3. Project Studies
4. Market Analysis
5. Human Resources
6. Chemical Labs
7. PhD in various sciences & fields
   

Sampling is used in the above scenarios because, in the above-mentioned fields and fields similar to that, research is widely conducted in order to gain in-depth insights with respect to that area of study.

Circumstances where sampling is not conducted:

Wherever there is a scope for general study, where there is no particular hypothesis to support or validate, sampling is not included. Mainly it is done in order to understand and get in-depth insights. For general study and knowledge, sampling won’t be required.

There are several stages in sampling process:

1. Defining a population which concerns your research
2. Giving your sample a frame (a set of items/events which could be quantified)
3. Specifying a sampling method for selecting items/events from the frame
4. Determining the sample size
5. Implement sampling plan
6. Sampling and data collection
7. Reviewing the sampling process.

Methods of sampling:

1. Probability Sampling
   1. Simple random sampling:
      1. A type of sampling method where every element of the parent population being studied (e.g.: human beings) have an equal chance to be a part of the research as a sample.
      2. There is no bias involved in selecting the sample.
         
   2. Stratified sampling:
      1. Commonly used probability sampling technique superior to systematic sampling.
      2. Stratification is the process of grouping members of the population into relatively homogenous subgroups before sampling.
      3. The strata should be mutually exclusive, i.e. every member/element of the population should be assigned only to one group or stratum.
      4. The random sampling should be applied within each stratum.
         
   3. Systematic sampling:
      1. In this case, each member for the research is chosen at a fixed or spaced interval for including them to be a part of the research. E.g.: out of 10000 people, being the population, if you would like 1000 people to be a part of the research, you would choose every 10^th person.
         
   4. Cluster sampling:
      1. Clusters are randomly selected and all individuals in these clusters are usually interviewed. This technique is used for a research or a study when the population is too vast or dispersed (geographically)
         
2. Non-probability sampling
   1. Judgement sampling:
      1. Most common non-probability sampling method where desired members for the study are chosen purposely or intentionally. This is done only to pick the important members representing the true characteristics of the whole population, relevant to the study being done.
         
   2. Convenience sampling:
      1. Used in exploratory research where the researcher is interested in getting an inexpensive approximation of a truth. People who are easily accessible from the population are chosen and data is gathered for the research.
      2. It is different because it is a non- probability sampling method
      3. The researcher has the freedom to choose whomsoever he finds convenient for the research.
         
   3. Quota sampling:
      1. It is similar to stratified sampling.
      2. Researchers first identify their groups or stratum
      3. Convenience or judgement sampling is used to select the desired number of members for the study from each stratum or group.
      4. This differs from stratified sampling, where the stratum is filled by random sampling, but here, the stratum is filled by convenience or judgement sampling.