Could you GO Measure Practical Economy?

I hope all the confusion with this post has been removed, I tried my best by commenting on your posts, hope it was helpful and the pictures in the last post sufficed you to write about criteria of sampling design. You girls know quite a bit about Criteria huh!!

Here’s what I think of these pictures and the terms:
1. Goal orientation: the picture shows a purple arrow pointing aimlessly and an orange arrow pointing towards goals. Sampling should not be done aimlessly like the purple arrow but like the orange arrow keeping in mind the goals of the study.

Goal orientation refers to making the sample design based on the goals and objectives of the study. In any study there are

· Tools and methods of data collection
· The expected outcome or hypotheses
· Or there may be a problem whose cause is to be found out.

These aspects have an impact on the selection of the sample. The objective of the study will be achieved only if they are correctly identified and applied to the sample.
· Tools and methods of data collection - In the first case if one thinks of administering an opinionaire then the related sample participants/items should be able to respond to it.

· The expected outcome or hypotheses – if the prediction is that by the use of charts the learners will get better in their visual representation skills, then those participants that are already good in their visual representation skills should not be selected.

· Or there may be a problem whose cause is to be found out – in this case it should be seen to it that the problem is present in the sample participants/items. For eg. If the study is to find out the cause of high dropout rate among rural school students then the participants selected as sample should either be directly/indirectly related to the problem.

2. Measurability

The picture shows a person measuring the length of wood. For a sampling design, this refers to selecting a valid sample that represents the population correctly. Selecting a valid sample means the numbers of participants/items that are selected from the population are enough to represent the entire population and have the necessary characteristics. A valid sample will give correct data, help infer correctly and hence result in conclusions which could be applied to the population. Thus measurability indirectly helps in making valid inferences from the sample which could be applied to the entire population.

3. Practicality
The reason I did not provide a picture for this is that the term itself gives away what this criterion is about. It says that selecting a sample theoretically is one thing but practically applying it is another. This criterion expects us to identify those aspects of a sample that affect its feasibility. Also the possible problems should be identified and solutions for it should be devised. Merging the theoretical and practical sampling design is what this criterion asks us to do.
For e.g. someone maybe interested in finding out the opinion of people on projected keyboards in computer handling, then in that case the people who have seen/used a projected keyboard may be very less or non existent thereby making it practically impossible to carry out the study.
As many of you have pointed out in their post, the issues we saw in accessibility of the sample may also contribute to this criterion.
4. Economy
The 3 pictures for this criterion are apt and say everything without one word being written, the 3rd picture is what must have thrown you off for a while. Let us start in line,

The first picture shows stacks of coins and a piggy bank in the background, which relates to the fact that the expenses for the study should be handled well without wastage. Meaning money should be spent only where it is required.
The next picture again tries to say,

that all activities should be well planned to accommodate the different phases of research and the schedule should be adhered to. Time should be invested only where it is required, i.e. it should be diligently used.
Coming to the 3rd picture,

it may seem a little confusing at first but slowly you begin to understand that some times research may not be dependant only on the researcher alone, there may be assistants to help with different tasks, say data collection, data inference, etc (depending on the magnitude of the research). In some studies statistical analyses may be done by experts and not the researcher. Such help may need to be paid or their time may be at stake. Hence economy also refers to using personnel judiciously, i.e. using only if they’re required as this may affect the other two aspects time and money.
We can say that a sampling design is economical when it balances time, money and personnel efficiently.

It is bound to happen that all these criteria cannot be attained to the optimum. As it may happen that to increase measurability the sample size is increased but that may decrease the economy of the design. Or for practical purposes if the sample was selected differently then it may affect the goal of the study. Thus it may not be always possible to have all criteria fully satisfied; however a balance between the four can be attained.