Question

Discuss data validity and reliability, Why are they important? How do data collection techniques impact data validity and reliability?

Answer 1

1.

Reliability implies consistency: if you take the ACT five times, you should get roughly the same results every time. A test is valid if it measures what it’s supposed to.

Validity simply means that a test or instrument is accurately measuring what it’s supposed to.

Tests that are valid are also reliable. The ACT is valid (and reliable) because it measures what a student learned in high school. However, tests that are reliable aren’t always valid. For example, let’s say your thermometer was a degree off. It would be reliable (giving you the same results each time) but not valid (because the thermometer wasn’t recording the correct temperature).

2. IMPORTANCE:-

validity

If the results of a study are not deemed to be valid then they are meaningless to our study. If it does not measure what we want it to measure then the results cannot be used to answer the research question, which is the main aim of the study. These results cannot then be used to generalise any findings and become a waste of time and effort. It is important to remember that just because a study is valid in one instance it does not mean that it is valid for measuring something else.

• Internal validity refers to the ability of the research design to rule out alternative explanations of the results High degrees of internal validity are associated with experimental design, where the effect of an independent variable on a dependent variable is studied under strictly controlled conditions. Medical research and clinical trials are widely used examples of experimental design.
• External validity concerns generalizability of the research findings. In other words, if the study is repeated in a different place or with different people, would the results be the same? A key factor for ensuring external validity is obtaining a sample that is representative of the population being studied.  

Reliability

• it lessens the chance that the obtained scores are due to randomly occurring factors, like seasonality or current events, and measurement error
• Measurement error can be reduced by standardizing the administration of the study, i.e. ensuring that all measurements be taken in the same manner among all the study participants

3.

A data collection method or instrument is consideredreliable if the same result is obtained from using the method on repeated occasions.” “A measurement method or instrument is considered valid if it measures what it intends to measure.

Validity

Are there any factors or intervening variables that should cause me to distrust these data?

Reliability

• Is this information an accurate representation of reality?
• Can I think of any reasons to be suspicious of its accuracy?

Triangulation-

There are ways to develop valid and reliable instruments without triangulation, but these methods are often problematic. First, they are time-consuming and frequently prohibitive in terms of cost. This is because significant field-testing is required to establish the validity and reliability of a measuring instrument. But even if teachers were willing to invest the time, money, and energy required to establish technical validity (construct and content) for their home-grown instruments, they probably wouldn't be happy with what they produced.