When you take samples on the basis of your comfort, it is called convenience sampling. The name "convenience" sampling is given because the selection of samples is done without any predetermined theories or principles.
Convenience sampling is not preferred way of sampling for effective analysis as samples are taken from specific section of the population. Convenience sampling is a type of Non-probability Sampling.
Convenience Sampling Example
When you are asked to survey about the habit of drinking alcohol in your town, you will not go and roam all around the town. What you will do is meet a few households around you and ask them about those who drink alcohol. It will not exactly reflect the position or characteristics of the town but it is still reflecting some major characteristics to some extent.
In the above figure, the pollster(person who conducts the poll) chooses items around it as the samples. The items in the colored square represent the items chosen as samples. This usually happens when the pollster is not asked to comply with the norms of the sampling expressly or s/he is ignorant to the effectiveness of the system.
Advantages of Convenience Sampling
- Easy Method
As Convenience Sampling allows the pollster to draw samples from the zone where s/he gets comfortable, the sampling method becomes easier for the pollster as compared to Stratified Random Sampling, Systematic Random Sampling and others.
- Represents class of data pollster is familiar with
As the Pollster chooses those items which are familiar with the environment of himself/herself, it becomes fruitful for understanding his/her environment.
- Less time consuming
The method can be conducted by taking only those items which are easier to choose and analyze. This makes the whole process less time consuming.
- Economic way of sampling
As this method puts its focus on the ease of the person who conducts it, and chooses the items which are easiest for examination, it is an economic way of sampling.
Disadvantages of Convenience Sampling
- Fails to represent the whole population
Since all the samples are concentrated around the person carrying out the survey, it can not represent the whole sample as a whole.
- Whole system may become useless
When the end users are in need of the information about the whole population, or when the end users' need of information do not match with the perception of the pollster, the whole system goes defunct.
- May not represent the whole population
Uneven distribution requires the system to choose samples more dispersedly. It is because more dispersed samples represents the population better. As the Convenience Sampling does not focus on choosing samples in more dispersed way, it can not be used for uneven population to draw conclusion on the whole population.
Why Convenience sampling is used?
Convenience sampling is useful for Pilot Project(trial project) that aims for getting information by selecting samples that are easier to study and satisfy certain criteria. Convenience sampling are useful,
- if the population is random.
- when the whole population is difficult to be studied thoroughly.
Convenience sampling is used for our ease as it's less time consuming and easier method. But, it is not preferred to use this technique for accurate analysis of population in all cases.