Purposive Sampling

PURPOSIVE SAMPLING

What is Purposive Sampling?

Kerlinger (1986) explained purposive sampling as another type of non-probability sampling, which is characterized by the use of judgment and a deliberate effort to obtain representative samples by including typical areas or groups in the sample.

A purposive sample is one in which a surveyor tries to create a representative sample without sampling at random.

In other words, Purposive sampling targets a particular group of people. When the desired population for the study is rare or very difficult to locate and recruit for a study.

For example: To study the life style of the young children of the construction workers near the construction site.It restricts the sample population to a very specific population and then tends to use all of the subjects available.

The power of purposive sampling lies in selecting information rich-cases, for in-depth analysis related to the central issues being studied.

Purposive sampling can be done in addition to probability sampling also.

For example: after completing your baseline study based on a random sample, you may recognize that certain sections of the project area are quite different from other areas due to variations in landscape, geography, culture etc.

You may then purposively select those areas to get representative information about how the variations have influenced the behavior of the people.

Uses for purposive sampling

• Validation of a test or instrument with a known population
• Collection of exploratory data from an unusual population
• Geographical areas to represent a larger area
  One of the commonest uses of purposive sampling is in selecting a group of geographical areas to represent a larger area.

For example: door-to-door interviewing can become extremely expensive in rural areas with a high population density. In a country such as India, it is not feasible to do a door-to-door survey covering the whole country. Though areas could be picked purely at random, if the budget was small and only a small number of towns and cities could be included, you might choose these in a purposive way, perhaps ensuring that different types of town were included.


Advantages

It is easy to undertake.

Disadvantages

It has a potential for inaccuracy in the researcher’s criteria and resulting sample selections.

Conclusion

In short, purposive sampling is best used with small numbers of individuals/groups which may well be sufficient for understanding human perceptions, problems, needs, behaviors and contexts, which are the main justification for a qualitative audience research.
Purposive sampling

References:

http://www.okstate.edu/ag/agedcm4h/academic/aged5980a/5980/newpage15.htm
http://www.wadsworth.com/psychology_d/templates/student_resources/workshops/res_methd/sampling/sampling_30.html
http://jan.ucc.nau.edu/~mezza/nur390/Mod3/sampling/lesson.html
http://www83.homepage.villanova.edu/richard.jacobs/EDU%208603/lessons/sampling.ppt#1

Mini Quiz

State True or False.

1. Purposive sampling is another type of probability sampling.

2. Purposive sampling does not require the researcher to describe in detailed methods used to select a sample.

3. It is possible to define purposive sample because the researcher uses clear criteria (e.g. experience & prior knowledge) to identify criteria for selecting the sample.

Simple random sampling vs Convenience sampling

This post is in reference to the post by Hemangi, named Let’s get sampling! on Friday, April 6, 2007

• Simple random sampling

1. Any one can get seleceted from the sampling frame.hence we say that each individual has a chance of getting selected randomly.
2. Sample is representative of that particular area.
3. The result obtained is applicable to all people or to all crieteria means it is generalized because of random selection.
4. Sample selection is without any bias.
5. The list of all individuals or sample frame is not readily available.
6. This method is also called as "lottery method."
7. This type of sampling is used in survey methods of reaesrch.

• Convenience sampling

1. The sample or individual is selected purposefully.
2. The item may not be representative of any area.
3. The result may not be applicable to all people or all crietria because of purposefull selection.
4. Sample selection is with bias.
5. The sample is selected from the nearest population which is easily available to the researcher.
6. This type of sampling is also called as "accidental sampling" or "opportunity sampling."
7. This type of sampling can be used in case study method of research.

Communication

Communication...





“The way we communicate with others and with ourselves ultimately determines the quality of our lives”
-Anthony Robbins

http://thinkexist.com/quotations/communication/






"The art of communication is the language of leadership."
— James Humes http://www.leadershipnow.com/communicationquotes.html

Connection..





“There is no necessary connection between the desire to lead and the ability to lead, and even less the ability to lead somewhere that will be to the advantage of the led….”
-Bergen Evans
http://thinkexist.com/search/searchquotation.asp?search=quotes%20on%20connection&page=2

The most basic and powerful way to connect to another person is to listen. Just listen. Perhaps the most important thing we ever give each other is our attention…. A loving silence often has far more power to heal and to connect than the most well intentioned words.
-Rachel Naomi Remen



Slogan

"Wherever you go, our network follows"
- Hutch in India
http://en.wikipedia.org/wiki/List_of_advertising_slogans#Communications.2C_broadcasting.2C_and_publishing

Karr Lo Duniya Mutthi Mein...........
-Relience Communication

Crieteria of Sampling Design

This post is in reference to the post by Hemangi, named Criteria of sampling design- GO Measure Practical Economy! (Sunday, April 1, 2007)

Crieteria of Sampling Design is explained with the help of following

• Goal Orientation: After seeing the picture one thing comes in mind that for every task there should be some specific goals,in order to complete it. Any research has a specific goal and based on it there are some objectives to fulfill the research.So sample should be choosen in such a manner it will fulfill the researcher's requirements.

• Measurability :It refers if sample size is considerablely small or many a times may be larger, the results should be measured accurately.The sample size should be managed by the researcher easily.If it is too small then it is easy for him/her to find the results accurately but if it is too large then it is problematic for the researcher to correlate all the information.

• Practicality: It is related to practicality of the research means the sample should be undergone the tsts.The samples should be actually engaged in a certain kind of work; practicing.

• Economy:It will depend upon the sample size.larger the sample researcher will have to spend more time,money for research and smaller the sample it will be economical. Having look at the pictures we come to know that time,money and people(who are helping in research) are also an important factors.

Accessibility of Samples

Hi Hemangi..

I am bit confused about this ,but what i feel i have posted here.Let me know whether i am correct.

1. I think there may be some chances that the participants may not be allowed for prticipating in the research because if participants are child they are having their exam, or they may be ill or their parents are not allowing them for being a part of research.
2. Some times access to sensitive areas might be problematical because in such cases the school drop outs ,drug addicts , or victims of bullying may refuse to share their experience cause they may feel that it will be openly shared with anybody and they will also have fear that their name will appear somewhere and they feel shy about their deed.
3. Access may be denied by potential sample participants themselves for very practical reason e.g.if in any case lowyers are being considered then they not have enough time from their busy schedule to cooperate researcher, as the lowyers may have many cases pending with them and many of them are being in process.

hi!!!!!!!!!!


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