Advantages Of Judgmental Sampling Over Other Sampling Methods

Published Date: 02 Nov 2017

There are two main types of sampling methods; probability sampling ad non-probability sampling. Probability sampling also referred as random sampling is one in which getting any scenario or results can be accommodated or calculated scientifically. For example, research on the usage of two particular mobile phone operators; that is the number or users from each operator can be calculated.

On the other hand non-probability sampling is a method used based on the prior knowledge of the subject being researched and on targeted samples who already have an expertise on the matter being interviewed for. Non-probability sampling is often used for social and psychological researches so as to get a broad idea about a massive population just by interviewing a random sample about that particular population. For example interviewing doctors about a particular drug that is being implemented in the health sector.

Judgmental sampling also referred as Purposive sampling is as non-probability sampling method of sampling that is based on the idea that the interviewer or researcher already knows what are the required qualities from the interviewees thus making them the proper ones for the study.

Purposive Sampling

In this sampling method, we sample with an objective or purpose in our mind. We usually would have one or several specific focus groups we are searching. Purposive sampling is very useful for situations where we need to acquire focus sample in a small time lapse and where sampling for symmetry is not the main concern. With a purposive sampling, we are likely to get the views of our target population, but we are also likely to overweight subgroups in our population that are more readily reachable.

Advantages of Judgmental sampling over other sampling methods.

This type of approach is better understood and straight forward compared to other sampling methods as the interviewer is already an expert in the field and the persons sampled are also well convenient in the topic. Also, judgmental sampling will be a better solution for this research as it is less time consuming as a large number of interviewers are not needed. Judgmental sampling will also be an advantage as no statistical knowledge is required. Also judgmental sampling method does not require vaste knowledge about mathematics and again as I have never done advance mathematics at secondary level this will be the best choice to carry out my research on teachers’ views on the topic.

Quantitative Sampling method.

Quantitative sampling is a method used to ask people about their opinions in a structured way so that hard facts can be obtained from them for analysis. Quantitative sampling can be used in the form of questionnaires consisting of a number of closed ended questions and these questionnaires distributed to a broad number of people who are aware of the topic or whore are not aware of it. For example distributing questionnaires to a number of people about consumption of soft drinks and their preferences and compiling the results to know about the consumption of a specific soft drink.

Advantages of using quantitative research.

This type of approach is more suitable for analyzing a large group of interviewees who may or may not be aware of the topic. Also results can be computed mathematically thus it is less time consuming by the use of statistical software like SPSS. This will be an advantage for me while interviewing students as there will be around 120 students to be interviewed and also these students will have to reply to close ended questions.

Composition of the chosen focus group of teachers.

Like mentioned above all the subjects to be interviewed were from the secondary education sector from different institutions so as to get a broader idea about the subject. The group which was chosen, consisted of 25 teachers, including 10 male and 15 female teachers from different institutions. Also, among the chosen teachers there was an equal ratio of age group, marital status, and level of education. Higher School Certificate, Diploma, BSc and Masters Degree, and lastly their level of experience. The sample chosen, though small in size will definitely give a broad view about how and why sex education can be introduced at secondary level.

Focus groups.

For the interview about whether sex education should be implemented at school, interview was chosen for some teachers as a qualitative means of research.

The focus group was chosen six to eight weeks back and some staffs from several institutions were chosen. They were asked if they could be interviewed and also in coordination with them chose the proper place and time for the interviews. Several factors like age, marital status, gender, level of education and also experience of the interviewees were considered so as to get the maximum information from all aspects.

Also factors mentioned above were chosen as they can play an important factor in introducing and teaching sexual education at school.

As mentioned these factors are and their usefulness are as follows:

Age: this factor will bring to light about the maturity of the interviewees also the co-relation about age and sex education and also whether the age factor will contribute in teaching sex education at school.

Marital status: this factor will also co relate teaching of sex education and marital status. We will be able to get an idea how being single, married or divorced can contribute in implementing sex education and teaching sex education by teachers.

Gender: This will be the most important factor as this will enable us to know which gender is more prone for implementing sex education and teaching it at school.

Level of education: this factor will determine how people with different education levels will tackle sex education at school and if further training must be given to them before the topic will be implemented at school.

Experience: Level of experience will give an idea how implementation of sex education at school will be tackled by different people, again considering the "why" and "how" factor.

Defining the different criteria while choosing the teachers to be interviewed.

Out of a population of approximately 500 teachers, it was a quite difficult task to choose only 25 of them. Again for this choice the preset criteria; that is; age, gender, marital status, level of education and experience.

As far as age factor was concerned it was an easy task as the interviewees were sampled by age groups of 25-35 years, 35-45 years, finally 45 and above. Concerning marital the sample consisted of married, single and divorced members of both sex. As for level of education, the sampling criteria were based on four different education levels; that is Higher School Certificate, Diploma, BSc and Masters Degree. Teachers’ level of education was also considered as criteria and this criterion was categorized as follows: less than 1 year, 2-5 years and finally 5 and upwards.

Designing the interview for teachers.

As far as the teachers were concerned, like mentioned above 25 teachers consisting of males and females were selected. Before going through the interviews emphasis on what makes a good interview and how to perform good interview were put.

According to (Creswell, 2007), "As common with quantitative analyses, there are various forms of interview design that can be developed to obtain thick, rich data utilizing a qualitative investigational perspective."

http://www.engin.umich.edu/teaching/crltengin/engineering-education-research-resources/turner-qualitative-interview-design.pdf

What makes a good interview

After some researches, it was deducted that the following practices lead to a good interview:

Making the interviewee feel at ease by choosing the right atmosphere.

Guiding the interviewee through the questions.

Face to face works better than questionnaires.

Avoid boredness through respecting the time limit.

Using the proper language or using the language in which the interviewee is more comfortable.

Never interrupt the interviewee while he/she is talking.

Good preparation work on the topic before the interview.

Clarify the purpose of the interview.

Clarify answers from interviewee when in doubt.

Using the right voice tone and speaking with a clear pace.

Give confidentiality assurance to the interviewee.

The interview process and questions asked.

For interviewing the teachers, I chose a face to face approach in order to know about the opinions of teachers as a whole. Questions were asked one by one and answers were noted and I case of simple answers, other sub questions were asked so as to encourage them to elaborate on their answers. Also their body language were observed and signs like if the interviewee is sweating, this might be a sign of not feeling at ease with the questions asked.

Before the interview started the participants were given the choice about choosing the spot and once there, they were greeted and presentations were made so as to make the participants fell at ease. The chosen teachers for the interview were given a briefing about the topic on which they are going to be interviewed s as for them to get a broad idea what was expected from them. This will enable for a better qualitative interview sample as the chosen focus group is already aware of the topic. Also the teachers were briefed to answer what they think thus not to be biased. After the briefing questions were asked in the proper language or dialect that suited the interviewee and their answers were note along with body language. Sub questions were asked in case of simple answers so as to elaborate an get exactl what the participant think.

After the interview the participant were thanked for their participation and some refreshment were served, which I had arranged before starting the interview.

The questions asked were as follows:

Is there a need to teach sex education in school? Why?

According to you, how sex education should be implemented in schools.

What are the benefits of teaching sex education in schools?

What are the obstacles, if any you may encounter while teaching this subject?

Have you ever encountered any problems with your students due to a lack of sex education at school?

Which gender according to you needs sex education/

According to you, in which class should sex education be implemented/

Composition of student focus group.

Students were chosen on a random sampling method; that is, they were chosen randomly from classes ranging from form 1 to HSC from different colleges and of both sexes. The total number of questionnaires distributed was 120 to the selected sample of students.

Form 1 to HSC and both sexes were chosen as all classes and gender in secondary level are concerned about sex education. Also students from different institutions were chosen so as to get a wider overview of answers.