Qualitative research aims at generating findings from real world settings or in its natural state, without attempting to manipulate the same. This method uses techniques such as observation, case studies, and interviews and does not apply statistical procedures or other means of quantification.
Qualitative Research stresses on the “why" and “how" of things rather than the “what," “where," and “when" of things. It aims at understanding the concept, illuminating reality, and extrapolation of the situation to other similar situations, rather than effect predictions, generalize, or make causal determination.
All research requires validity and reliability. Validity shows the soundness of the research methodology and the results generated, based on the extent to which the research remains in congruity with universal laws, objectivity, truth, and facts. The validity of statistics driven quantitative research depends on the soundness the instrument adopted. Validity in qualitative research however depends on the ability and effort of the researcher, as the researcher is the instrument.
Credibility refers to believability or reasonableness. Credibility as an element of validity of qualitative research denotes the extent to which the research approach and findings remain in sync with generally accepted natural laws and phenomenon, standards, and observations. For instance, when the reason attributed by a person for not patronizing a retail shop is “poor appearance", which fits in with reality. However, another reply, that a person does not patronize a retail shop because “aliens prevent him from going near the shop" is strange and not credible according to scientifically held convictions.
Qualitative research however involves recording the participant experience and insights, and as such, only the participants themselves can evaluate the credibility of the research. In the example quoted above, a participant may indeed feel aliens and UFOs have a controlling their actions, and the role of the researcher is to record such observations.
External validity in quantitative research refers to the extent to which the same methodology applied to another set of sample works in a similar way and produce similar results. Qualitative research does not require external validity, for each research is unique and has different settings. The validity of qualitative research depends rather on transferability. Transferability is the ability to generalize, or the extent to which the results of the research apply to other contexts or settings.
Qualitative research with descriptive research context and assumptions generally has greater transferability compared to research with lesser descriptive contexts and fewer assumptions. For instance, a study on customer patronage of a retail store specifying the size, turnover, range of items on stock, demographic profile of the locality, and other factors easily transfers to another store of a similar size and setting, but not to a hypermarket.
The application of transferability however remains subjective, and depends on the specific case. For instance, generalizing the findings of a research regarding the culture of religious schools to other religious schools of the same denomination in the same state tests the validity of the study, but generalizing the same research to a community college in another state is foolhardy.
Quantitative research requires the characteristic of reliability, or repeatability to become reliable. Reliability is the obtaining the same results when repeating the exercise. Qualitative research however does not need reliability, as it is not possible the measure a same thing twice even using the same focus group, and repeating the observation would mean undertaking a second study.
Qualitative research requires dependability rather than reliability. Dependability is the description of changes that occur during the course of research, and an understanding of how such changes affect the research or the study. For instance, in a qualitative study on customer patronage of a retail store in a residential area, summer vacations may witness an unexpected decline in patronage as people go on vacations. A valid research factors in this trend.
Conformability is the degree to which others agree or corroborate with the research findings. Each qualitative research is unique in itself, but the researcher can still adopt means such as documenting the procedures for rechecking data, unearth negative instances that contradict previous observations, play devil’s advocate and more to ensure conformability.
For instance, in a study on customer patronage of a retail store, the researcher can cross-check data generated on the number of visitors to the store and their buying preference to the sales billing maintained by the store. The researcher can also refer to earlier studies or market research that may cover a similar sample, even if the purpose of such study was different, and more.
The above mentioned measures of credibility, transferability, dependability, and conformability are subjective in nature, and such values apply for quantitative research as well. One school of thought argues that since each qualitative research is unique, validity is not applicable, and needs replacement by a qualifying check or measure for each variable. This is however a minor opinion and most experts consider qualitative research that displays qualities of credibility, transferability, dependability, and conformability as trustworthy and valid. Researchers who succeed in making a strong association with all such measures can rank their research high in validity.