In short, you can apply the findings of your research to a larger audience. External validityД®xternal validity refers to the extent to which the outcomes of the research can be generalized to the population.

In experimental designs the researcher needs to be very careful in measuring the variables, the external variables can have an impact on the outcomes of the research and it can ruin the research. In-other-words there is a causal relationship between the independent and dependent variable. (2007) states that internal validity refers to whether the effects observed in a study are due to the manipulation of the independent variable and not some other factor. An inaccurate research design and techniques cannot yield accurate and valid results. In other words, it is the accuracy of the internal design that needs to be controlled by the researcher. Internal validity refers to the accurateness of the data collection tools, procedures, and techniques. There are two types of validity important to measure in a research: internal validity, and external validity. The concept of validity was formulated by Kelly (1927) who stated that a test is valid if it measures what it claims to measure. (2000.b) in his book Research Methodology states that to establish the validity in research, the researcher should use logic and statistical evidence. Therefore, the first step to achieve validity in a research is to develop objectives that really target the questions that you have formulated. To achieve validity one needs to use the right tools, processes, and methods in the research.ДЄccording to Kerlinger, вЂthe commonest definition of the validity is epitomized by the question: Are we measuring what we think we are measuringвЂ™. When we measure what we have intended to measure we reach a conclusion that is valid and verifiable. It is the highest aim every researcher wants to achieve. Validity refers to the accurateness of the research as a whole and the accuracy of each step independently. The resultant scores of the test are correlated to know the internal consistency reliability. The researcher might divide the questions on the questionnaire in half and administer both questionnaires separately. For example, the researcher has developed questionnaire to test the attitude of people towards any state program. Each half is tested separately and then their scores are correlated. It means that the items that test the attitude or behavior, are divided into half. (2000.a) in Research Methodology stated that he idea behind internal consistency reliability is that items measuring the same phenomenon should produce similar results. This type of reliability test is useful for subjective measures where more than one rater can best describe the reliability of the test.

The researcher asks more than one people to rate the reliability of his test. More than one tester or judge uses inter-rater reliability check to measure reliability. In social sciences, using parallel forms of same test is difficult and the issue of subjectivity arises. The researcher may also find it difficult to administer it to two similar populations. But the difficulty arises in formulating two tests that are similar in nature and measurement level. The researcher must be able to formulate two different tests that measure the same variables. Both forms of the test measure the same variables under study, but the format of the measure is different. It measures the reliability of the test by administering it in two different forms. But, this method of testing the reliability of the test is time-consuming, since the researcher has to wait for some time to re-administer the test. The results of the tests and the inferences drawn have to be applied to natural settings, they should be reliable. In natural sciences, the researcher conducts experiment more than one time to ascertain its reliability. In social sciences, a test is administered more than one time over a period of time to check or retest its reliability. Test-retest reliability measures the reliability of the measure over a period of time. Types of reliability Test-retest reliability For example, rigor and control, sample representativeness, clarification, and justification are some ways to improve reliability in qualitative research. There are certain techniques that can help improve reliability in a qualitative research.

Data validity and reliability