Quality is
fundamental in any type of research. The two aspects of quality in research are
reliability and validity. There are types of measures used to assure that the
study is reliable and valid. Sampling pertains to the determination of the who
and what should be included in the research. These are the subjects who will be
observed, interviewed, or tested during the study.  There are attributes that constitute trustworthiness
or rigor of a research such as credibility, transferability, dependability, and
confirmability. There are two case study samples that are reviewed in terms of
its sampling, reliability, validity and trustworthiness.
















Reliability, Validity and Trustworthiness   

            Part of the planning phase of
research is to aim at sampling, reliability, validity, and trustworthiness in
research. The benchmarks are established to assure reliability and validity of
a research study. These terms are further defined to understand their
differences and purposes as applied during research process. One important goal
in research is to introduce randomness and prevent application of a system that
could include biases.

Application of Sampling, Reliability and
Validity on a Case Study Review

are two major types of sampling: qualitative sampling and quantitative
sampling. There are sub-types under each type. Sampling consists of who and
what to be included in the test. There are two general questions that must be
addressed prior to selecting your required samples: the size and the
composition (Tappen, 2016). Sampling is also defined as the process of finding
a representative of a chosen population for the intention of establishing
parameters or attributes of the entire population (Robert, 2015). There are
certain terminologies that are constantly used in research sampling which must
be identified and understood beforehand (Harvey, 2012-17). First is population. It is defined as the group
of people a researcher is interested in including in the study. Second is parameter. It is defined as characteristic
of a certain variable regarding the population. Third is sampling frame. It is the list of the entire population the
researcher is interested in. Fourth is sample.

It is the subgroup of people from a sampling frame or population. Fifth is representative. It refers to the sample
that has the same attributes of the population. Sixth is generalizable. It is the ability to generalize the data to the
population. Seventh is sampling error.

It is the difference between a parameter and a statistic.

probability sampling and non-probability sampling are two types of quantitative
Sampling. Non-probability sampling is like convenience sampling but non-generalizable.

On the other hand, convenience sampling, purposeful sampling, and theoretical
sampling fall under qualitative sampling. Convenience sampling is the least
scientific and lacks intellectual credibility while theoretical sampling is
based on grounded theory which is more discriminant.

term reliability can be replaced by numerous synonymous words but according to
R. Tappen (2016), it involves research study or survey that produces consistent
results. There are questions a researcher must ask to address reliability. For
instance, if two subjects in the same scenario use the same measure, will one
arrive with the same results? Or, what if two different situations were used,
would the results be the same? These are just couple of questions among many to
measure reliability.  

points at how accurate a study or survey is at measuring what it is attempting
to measure. It emphasizes the measure being used is accurate to its deliberate
purpose (Tappen, 2016). The validity of a measure in research is deemed
critical. The goal of validity is to be as accurate as possible. There are several
types of validity: face validity, criterion validity, construct validity, and
content validity.  

Sample Case: Stress Management for Patients with Rheumatoid Arthritis (Prime,

case study is about a 40-year-old woman who has been followed up by a nurse
practitioner for rheumatoid arthritis (RA). She was diagnosed a year and a half
ago for moderate RA and was prescribed with an antirheumatic drug. About two
months before her visit to the clinic, she experienced flare-ups of her
symptoms (pain and swelling). At that time also, she was experiencing more
stress at work after receiving a promotion. Her diagnostic tests included
increased inflammatory hallmarks. She verbalized her worries of finances and
she was curious whether these symptoms are attributed to her current stress
level. She also wanted to know if there are other avenues to lower her stress
and reduce her symptoms.

background research done on this study revealed that RA affects a small
percentage of the population. The presentation of this autoimmune disease
includes damage on the joints which can eventually lead to considerable
disability and with a possibility of mortality. Clinical evidence shows that
added psychological stress can increase these symptoms. There is a strong
connection between minor stresses and exacerbation of RA. A 5-year study also
proved that those patients with higher stress level experience more joint
swelling than RA patients with lesser stress. On the hand, another study shows
that RA patients experiencing disturbances in mood have higher inflammatory
attributes with joint pain. Some research shows that behavioral interventions can
provide safe and money-saving benefit to RA patients. Some of these behavioral
interventions include cognitive behavioral therapy (CBT), tai chi, yoga, and
stress management education.


            Based on the information
available in this case study, the sampling technique used is qualitative sampling
which could either be purposeful sampling or theoretical sampling.  Purposeful sample is the sample of
participants, those with RA condition, who are purposefully considered for the
study because of their common experience with RA. On the other hand, it could
also be a theoretical sample, where the sample of participants, because of
their diagnosis-related experience can help in the development of a theory (for
example, RA patients who perform tai chi presented an increase in endurance and
strength of their lower limbs).

are discrepancies and inconsistencies in the results of use of behavioral interventions
such as CBT, tai chi, yoga, and education. Some are inconclusive and need
further studies due to the limitations of the study. Other results suggest that
although the benefits are unquestionable, the long-term effect and degree of
effect of these interventions are yet to be studied further.

evident by the inconsistencies of results, it suggests that the reliability and
validity of this case study is a concern. In terms of reliability, there are
not enough details regarding the process on how the behavioral interventions
were conducted (for example, different amount of time applied on the study of
yoga and CBT). Also, not enough information on how samples (patients with RA) are
tested or rated. In terms of validity, is the study accurate enough in
measuring what it is trying to measure? Unfortunately, in this study, there are
many factors such as pain ratings, levels of anxiety, anatomical differences,
degree of RA symptomatology, different kinds of stressors, should have been
considered before the study.          

Rigor in Qualitative Research

must be ascertained in any type of research. Quality is fundamental. Rigor is referred
to the compliance to the quality standards in conducting research to increase
the assurance in the results. To assure rigor in research, the method in
answering the intended research question must be appropriately addressed and
the chosen research design must be strong. Researchers believe that without
proper rigor, a research is bound to be no worth. Therefore, there must be a
general criteria or quality measured standards in evaluating research studies. Rigor
in research is attributed to the trustworthiness of the research.

Trustworthiness in qualitative research describes four basic elements:
credibility, transferability, dependability, and confirmability (Tappen, 2016).

described by R. Tappen (2016), credibility is identical to internal validity
which can be accomplished through five different ways. First, is by having enough
time to persistently engage, observe, and test for possible reason and outcome.

Second, is by reviewing and sharing your raw notation, interview transcripts or
preliminary outcomes to your participants or representatives of the people you are
working with to gain input or feedback from them and later include those
feedbacks in your conclusion. Third, is by including feedback from experts in
that particular study: methodology or subject. An objective critiquing of a
study takes time and interest on the part of the expert but can yield a
trustworthy result. Fourth, is by providing and considering other possible explanations
on participants’ negative viewpoints or data. The existence of the negative
cases must not be ignored and must be analyzed and reported regardless of its
impact. Fifth, is by referencing or cross checking two or more data to provide wider
perspectives that can be valuable in your complex study.

as noted by R. Tappen (2016), is parallel to external validity. In quantitative
research, transferability refers to how findings are applicable to other people
and situations thus can be generalized. Dependability, which is similar to reliability,
can be achieved by creating an audit trail while research is underway. Audit
trail covers a recorded compilation of your notes, researcher’s thought process
and reflections, survey guides, data, and including decisions during the study.

Confirmability as R. Tappen (2016) describes is the objectivity specifically in
quantitative research. The inclusion of a reflexive journal, which includes recorded
expectations and ideas prior to the study, which can support a researcher as
reference while answering his research questions.

Sample Case: Young Adult E-Cigarette Users’ Reasons for Liking and Not
Liking E-Cigarettes (Pokhrel, Herzog, Muranaka, & Fagan, 2015)

            The objective of
this study is to have a wider understanding of what young adults, ages 18-35, who
are users of electronic-cigarettes, like or dislike about electronic-cigarettes
or e-cigarettes. This study focused on determining the reasons of encouragement
and discouragement from the use of e-cigarettes. There were focus group
discussions conducted. Data gathered and analyzed with results indicating 12 classifications
of rationale on liking e-cigarettes while 6 classifications of rationale on the
dislike of e-cigarettes. The study’s conclusion provided the motives of the
young adults for the use and not use of the device. Their motives vary in
relation to the importance of its use. The findings also show that e-cigarettes
users, although purposefully served for social and recreational, do not depend
on just the nicotine effect. In addition, this study also discussed the
efficiency of the delivery of nicotine, smoking cessation, and device


            This study proved
to be trustworthy and here are the reasons why. In terms of its credibility, a 4-month study was
sustained sufficient to engage and observe the participants. Triangulation was
also used in this study, allowing data cross-checking for inconsistencies. The
researchers of this study, not only included the strengths of this study but
also included the limitations which constitute negative case analysis. In terms
of dependability, the investigators,
coders, and note takers have used questionnaires, surveys, notes,
audio-recorders, and have reviewed their transcriptions and notes. They also
discussed areas of agreement and discrepancies. In terms of confirmability, just like the audit
trail, the researchers used a reflexive journal where methods and data
collection were logged including nonverbal responses of the participants.

Although personal thoughts or preliminary reflections by the researchers were
not stated in the study, reviewing of their transcriptions regarding
discrepancies and addressing them was mentioned in the study. In terms of transferability, this qualitative research
cannot be generalized. The results are specific to the focus age of 15-35, thus
cannot be validated externally. Nonetheless, the overall trustworthiness of this
study is high.  


            The type of sampling utilized in
research affects the accuracy of the results. A qualitative sampling was used
in the first sample case study. Although, in this same study, the validity and
reliability are in question as evident by the inconsistencies of results. In
the second sample case, the trustworthiness of the study is proven high based
on the parameters of quality rigor in research. Validity, reliability, and
trustworthiness in research are essential.