Evaluation Of Two Empirical Studies

Evaluation Of Two Empirical Studies

In the study “Prevalence of Prostate Cancer among Men with a Prostate-Specific Antigen Level ≤4.0 ng per Milliliter” by Thompson et al (2004) set out to undertake a study aimed at investigating prevalence of prostate cancer among men with a prostate-specific antigen level less than or equal to 4.0 ng/mL. In a slightly different fashion and approach, Kelly et al (2008) undertook a study titled “Learner Outcomes for English Language Learner Low Readers in an Early Intervention” that aimed at investigating the “efficacy of Reading Recovery (RR) with first grade English language learners (ELLs) in U.S. schools by evaluating the literacy effects of ELLs in comparison with their native English- speaking (NES) counterparts, who were also enrolled in the same RR.” By focusing on the two above mentioned studies, this discourse looks at the approaches each study used in terms of research rationale, philosophical basis, methodology used, extent to which the research objectives were formulated and achieved and conclusions derived from the entire study after conducting the research study. To achieve this, the discourse takes a convergent approach by focusing on each subject matter and delving by the first research study before moving on to the second. The study by Thompson et al (2004) opens the assessment followed by the study by Kelly et al (2008).

Thompson, I. M. et al (2004) Prevalence of Prostate Cancer among Men with a Prostate-Specific Antigen Level ≤4.0 ng per Milliliter. New England Journal of Medicine, 350:2239-224,

With respect to study objective, the research study the main objective of the study was to investigate the prevalence of prostate cancer among men with a particular antigen that is prostate-specific with antigen level less than or equal to 4.0 nanograms per milliliter. From the objective, it is evident that data gathering must involve real measurement to establish if the antigen level is within the desired levels.

Approach and Methodology

The first part of the methodology research critique looks at the study conducted by Thompson et al (2004) that sort to investigate prevalence of prostate cancer among men with a prostate-specific antigen level less than or equal to 4.0 ng/mL. The study identifies its corporate sponsor as the National Cancer Institute. In terms of sampling technique, the study used random sampling to come up with a sample size comprising a randomly selected sample drawn from 18,882 men based on fulfillment of initial selection criterion that entailed having no more than 3.0 ng per milliliter prostate-specific antigen. Other qualifications for the selection included the patient being at least 55 years of age, having a normal digital rectal examination, exhibiting an American Urological association symptom and posses no clinically significant coexisting conditions. This was a good start based on the fact that the criteria laid down for selection would reduce possibility of erroneous conclusion.

Research ethics and consent are very important aspects of any research study involving human subjects since the participants must not be coerced (Creswell, 2009). The study points out that the participants gave their written informed consent and that this was based on the fact that the participants had been provided with the details of the study. Since the study had different stages or phases, each phase mattered for the purpose of participants’ informed consent hence some participants who were eligible for the inclusion the final sample did not consent to undergo biopsy. Despite this, the study drew a connection between declining to undergo biopsy and age noting that those who declined were older than 75 years at 99% confidence level.

On the part of methodology, as already explained above, stratified random sampling was used whereby participants were randomly selected after meeting some initial qualifications. The study design took a randomized quasi-experiment approach with a placebo-controlled group included (Creswell, 2009). The PSA (Prostate-specific antigen) measurements were carried out in one central laboratory. This sounds like a good measure to ensure that same conditions are prevalent for all the measurements and accountability is easier to track. The study took a period of over 7 years. While the study reported that eligibility entailed, among other factors, having PSA level no more than 3.0 ng/mL and at another time having no more than 4.0 ng/ml, those who were found to have the PSA level more than 4.0 ng/mL were recommended for prostate biopsy.

Therefore, from the initial setting of standards for the study, there seems to be a confusion of whether the study took 3.0 ng/ml or 4.0 ng/mL to be the threshold of PSA levels. Nevertheless, there is a reason provided for including those having more than 4.0 ng/mL PSA levels in the study. The study included them as a measure to ensure generalizability of prevalence of prostate cancer for men with PSA ≤ 4.0 ng/ml to the general population. Therefore, only the control group (that was given the placebo) was used for the analysis. Among other features, the study assessed the relationships among base-line characteristics and prostate cancer. Therefore, prostate cancer was the dependent variable while independent variables included prostate-specific antigen.

Analysis and Results

The study used a confidence interval of 99% hence rejection or acceptance of a hypothesis was based on a p-value of 0.001. Final sample size included for data analysis was 2,950 men. Average PSA level for 96.2% of the initial participants is reported to have been found to exceed 7. At the end of study biopsy the study established that about 15.2% of the 2950 men had prostate cancer when end-of-study biopsy was carried out. However, there was no significant difference in cancer between those who underwent sextant biopsy and those who underwent biopsy with more than six samples taken.

The study identifies limiting factors that might have hindered the ability to detect correlation between age and risk of cancer given that risk of cancer increases with age. These factors included setting age limit for inclusion for participation and setting PSA level to 4.0 ng/mL. However, these factors helped in setting the control group which was administered with placebo. The study found a positive correlation between PSA and risk of prostate cancer noting that during the seven-year period of the study there was an annual increase in PSA levels noted among 449 men who had prostate cancer. The correlation was however not significant. The 449 men with prostate cancer had PSA mean of 1.78 ng/mL with standard deviation of 0.92 ng/mL as compared to the 2501 who had no prostate cancer and who had a PSA mean of 1.34 ng/mL with 0.86 ng/mL standard deviation.

It can be concluded that the study effectively accomplished its objectives of investigating the relationship between PSA levels and prostate cancer and its stage-wise approach allowed to even come out with supplementary findings. For the recommendations for future inquiry and professional nursing practice, the study recommends that even men with lower PSA levels should be screened for cancer as the results point to the possibility of men with lower PSA levels having cancer (also Krumholtz et al 2002). Therefore, they recommend a change in the practice cancer diagnosis.

Kelly, E. P., et al (2010) “Learner Outcomes for English Language Learner Low Readers in an Early Intervention” TESOL QUARTERLY Vol. 42, No. 2, June 2008

Approach and Methodology

From the outset, the study by Kelly, et al takes a mixed methodology approach to investigate how learner outcomes for English learner low readers differ from those of the English language learners. Even though the researchers do not explicitly indicate that they used the mixed methodology approach, a few characteristics of the mixed methodology are sufficiently indicative of it being used. First, the researchers used both qualitative and quantitative approaches to achieve the objectives of their study. For instance, measurements are carried out to establish the triple jeopardy of socio-demographic risk, low reader and ELL status and the outcomes for the associated students.

In matters concerning the sampling procedure and inclusion into the study, the researchers mention that inclusion into the study involved careful purposive sampling technique that ensured that the readers included in the study had reading level of 20% and below. Using this technique, the researchers came out with 8,581 ELLs and 121,961 Native English Speakers that undertook the RR program for school year covering between 2002 and 2003. It is notable that from the start of the research study, the researchers endeavored to place the study in theoretical settings and explain the study using theoretical frameworks such that even categorization of children in terms of English readership using the 4 levels helps the study in classifying the participants at the beginning of the research and at the end of the study when it is necessary to gauge the efficacy of the RR program.

From the qualitative study point of view, the study has several elements that clearly fit into a phenomenological study in that it involves collection of in-depth information and insights relating to the English language readership and these are initially achieved through extensive observation of the participants using several inductive, qualitative techniques. Other methods that are used by the researchers that help in boosting the claim of a phenomenological qualitative approach include the use of interviews, participant observations, interviews and discussions. Creswell (2009) note that phenomenological qualitative approaches take a different direction from other qualitative approaches by focusing on illuminating the precise subject matter and identifies phenomena through the way they are recognized by the actors in the particular situation.

Creswell (2009) further notes that, when conducted in the human sphere, phenomenological approach usually translates into collecting deep information and insights by use of inductive, qualitative techniques, which include interviews, participant observations and discussions. The information gathered through these techniques is presented from the research participants’ perspective. Therefore, phenomenological approach is focused on studying experience from the perspective of the individual and subjective knowledge of the individual in a way that emphasizes paradigm of personal perspective and interpretation. The approach is helpful in boosting understanding of individual’s motivations or actions while transcending the muddle of assumptions that are taken for granted and other conventional wisdom. It is further reasonable to argue from the perspective of a phenomenological approach from the formulation of research questions that are provided in the results at the end of the study. For example:

“Is the rate of students who discontinue successfully their series of lessons comparable between ELLs and NESs? lb. Do both groups have similar outcomes on the text reading and phonemic awareness tasks?” Kelly et al (2008, 247)

Comparison of Methodologies

With respect to comparison between the two studies, the study by Thompson et al (2004) used a quantitative research where numerical data about the patients was collected. The quantitative data was then quantitatively analyzed. On the other hand, the study by Kelly et al (2008) employs a mixed methodology approach with triangulation design through the convergence model. Creswell and Plano Clark (2011) describe triangulation mixed methodology as a strategy that can be explained as a single-phase research design where both qualitative and quantitative methods are implemented within the same time frame. This therefore brings out a clear understanding of the triangulation mixed methodology as involving qualitative and quantitative techniques in a similar time frame.

While the triangulation design has various approaches, the convergence triangulation model is employed when it is desired that the quantitative and qualitative data should be merged concurrently (Bazeley, 2007). This approach allows for thorough comparison of data hence brings out a better understanding of the phenomenon being investigated. Therefore for the research study by Kelly et al (2008), it must have been desirable that qualitative aspects of the study such as lesson designs and structure and the quantitative aspects such as the measurements of the words read to enable the categorization as used by the researchers.

With respect to whether the researchers take a deductive approach or inductive, research study by Kelly uses deductive research approach which is a type of reasoning that works from a more general to a more specific area. The research begins by formulating research theory from which the hypotheses are developed which are then evaluated and confirmed based on the observations generated from formulated study approach. It can be seen that the other research study by Thompson et al employs an inductive research approach, which works contrary to the deductive research approach in that for the study by Thompson et al (2004) the researchers work from specific observations developed by observing the various patients and participants and then develop these specific observation into broader generalizations that can be applied in other broader sense settings and situations of similar conditions. For the study by Thompson et al (2004), the researchers or investigators collect data from the field to facilitate him/her to develop a theory in inductive research approach (Creswell & Plano Clark, 2011).

An important question that must be tackled is how the two studies deal with the issue of generalizability of their findings. The two studies, while dealing with totally two different topics and areas of study, were chosen for the way they approach generalization of their findings despite taking greatly diverse kind of participants. In the study by Thompson et al (2004), the researchers based their inclusion on PSA levels less than or equal to 4.0 nano-grams per milliliter. However, the study also included individuals having more than 4.0 ng/mL PSA levels in the study. The study included these individuals as a measure to ensure generalizability of prevalence of prostate cancer for men with PSA ≤ 4.0 ng/ml to the general population. Therefore, only the control group (that was given the placebo) was used for the analysis. For that study, prostate cancer was the dependent variable while independent variables included prostate-specific antigen.

On the other hand, the study by Kelly et al (2008) focused on comparing native English speakers and English speakers whose first language is Spanish. This alone would warrant generalization of the results and conclusions drawn from the study to the general population. Nevertheless, Kelly and the fellow researchers in the study still found a reason to generalize the findings to the general population of English Low Learners. This was achieved by invoking theoretical models already introduced at the beginning of the study and also referring to past studies that had similar findings but which targeted English low learners of other racial descent.

In summative perspective, it is notable that while the two studies took totally different perspectives in the research approach and dealt with topics of totally diverse nature, there was ample realization implications of the study findings must be well articulated and generalization well established and justified. This justification must not necessarily be expressly highlighted but it can be deduced from the way the whole generalization issue is achieved. Secondly, the study conducted by Thompson was basically a quantitative one and issues dealing with validity and reliability are emphasized through the scrutiny of instrumentation used.

In contrast to the above, the study by Kelly is more of qualitative than quantitative and the issues relating to validity or reliability are handled through scrutiny of credibility, dependability and transferability of the results. For qualitative research, internal validity is taken as credibility and this involves ascertaining that the results of the qualitative research are credible from the point of view of the participant. The external validity as applicable in quantitative research is referred to as transferability in qualitative research and it basically entails the extent to which the results can be generalized with respect to other related contexts and settings. This is increased through subjective judgment and thorough description of context and underlying research settings.

With respect to validity, qualitative research calls for dependability by assessing the need for accountability of the researcher in terms of the ever-changing context within which research studies are conducted. Therefore, while Thompson et al (2004) were justified to undertake random sample of participants, ensure consent and take measurements seriously to ensure validity and credibility, Kelly et al (2008) were justified when they thoroughly described the underpinning contexts and settings of the research study and then also provided an account of the ever-changing context within which the research study was conducted. These measures ensured generalizability to have a strong philosophical backing.


Bazeley, P. (2007). Qualitative data analysis with NVivo. Thousand Oaks, CA: Sage Publications, Inc

Creswell, J. W., (2009). Research Design: Qualitative, Quantitative, and Mixed Methods Approaches, (3rd Ed.). Thousand Oaks, CA: Sage Publications.

Creswell J. W., & Plano Clark, V. L. (2011) Designing and Conducting Mixed methods research. (2nd ed.) Thousand Oaks, CA: Sage

Krumholtz JS, Carvalhal GF, Ramos CG, et al. (2002) Prostate-specific antigen cutoff of 2.6 ng/mL for prostate cancer screening is associated with favorable pathologic tumor features. Urology 2002;60:469-473

Pauler DK, Gower KB, Goodman PJ, Crowley JJ, Thompson I M. (2003) Biomarker-based methods for determining noncompliance in a prevention trial. Control Clin Trials New England Journal of Medicine,;23:675-685

Thompson I. M, Goodman PJ, Tangen C. M, et al. (2003) The influence of finasteride on the development of prostate cancer. New England Journal of Medicine, 349:215-224

Thompson IM, Tangen C, Goodman P. (2003) The Prostate Cancer Prevention Trial: design, status, and promise. World J Urol 2003; 21:28-3

Thompson, I. M. M.D., Donna K. Pauler, Ph.D., Phyllis J. Goodman, M.S., Catherine M. Tangen, Dr.P.H., M. Scott Lucia, M.D., Howard L. Parnes, M.D., Lori M. Minasian, M.D., Leslie G. Ford, M.D., Scott M. Lippman, M.D., E. David Crawford, M.D., John J. Crowley, Ph.D., and Charles A. Coltman, Jr., M.D. (2004) Prevalence of Prostate Cancer among Men with a Prostate-Specific Antigen Level ≤4.0 ng per Milliliter. New England Journal of Medicine, 350:2239-2246

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