Epidemiology, quantitative research

Structured 3,500 word essay maximum excluding the 954 words of the questions and your list of references
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Study assessed: Active by choice today, D Wilson principal investigator
QUALITY ASSESSMENT TOOL FOR
QUANTITATIVE STUDIES 218313015240000
COMPONENT RATINGS
A) SELECTION BIAS
(Q1) Are the individuals selected to participate in the study likely to be representative of the target population?
1 1. Very likely
2 2. Somewhat likely
3 3.Not likely
4 4. Can't tell
5
Provide your explanation:
Given the primary aim of the study- to determine the effect of behavioural and motivational skills intervention on the rate of physical activity among low-income and minority adolescents, the study's sampling technique was appropriate and representative of the target population. Participants were drawn from low-income families and public schools providing free or reduced lunch meals. The provision of free lunch is one indication that the children came from poor backgrounds. In addition, the researchers aimed at improving physical activity within this group, and for the purpose of testing the efficacy of their intervention method, they selected participants who were likely to have low physical exercise levels, and lacked home facilities or opportunities to engage in vigorous and regular physical exercise. This is because the participants came from poor neighbourhoods where access to recreational facilities like gyms and playgrounds is limited. In addition, the researchers selected participants from individuals who met a certain criteria- were overweight or at risk of being obese, had a mean age of 11.3 years, and were school going (6th graders). They state that “73 percent were African-American,” which is a minority group in the U.S. society, while “fifty-one percent “were in the 85th percentile of being overweight or obese” (Wilson, et al., 2011, p. 466). The inclusion of female participants (fifty-four percent) completed the representativeness of the sample because girls are a minority or underserved group in terms of opportunities for physical exercise. The traditional definition of gender roles and gender socialization confines female members in society to duties and responsibilities that prevent them from engaging in vigorous physical and other outdoor activities. For instance, women are socialized into domestic tasks, which confine them indoors most of the time.

(Q2) What percentage of selected individuals agreed to participate?
1 1. 80 - 100% agreement
2 2. 60 – 79% agreement
3 3. less than 60% agreement
4 4. Not applicable
5 5. Can't tell
6
Provide your explanation:
The total number potential subjects assessed for eligibility were (n= 1563). Out of this number, 141 did not participate due to the following reasons:
* 55 refused to take part in the intervention program
* 16 did not meet the selection criteria
* 9 moved to other schools that were not included in the randomized selection
* 60 were alternates
* One subject failed due to unexplained reasons (Wilson, et al., 2011, p. 464).
This brings the total number of subjects who were selected but did not participate to 141 pupils. Subtracted from the original total of 1563, it gives 1422 as the final number of participates. 1422 divided by 1563 equals 0.91, which gives 91 percent when multiplied by 100. This percentage is well within the 80-100% range.

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Provide your explanation:
The researchers used a sampling approach that was appropriate for selecting a sample population representative of the targeted group. They used baseline measures to determine who was eligible for the intervention program. This approach will increase the validity of the research findings, and give results that can be reproduced by other studies using a population sample with similar characteristics (Gerrish & Lacey, 2010, p. 144). In addition, the participation rate was sufficient to produce reliable results. A participation rate of 90 percent from a sample size of 1563 subjects is a big success.

B) STUDY DESIGN
Indicate the study design
1 1. Randomized controlled trial
2 2. Controlled clinical trial
3 3. Cohort analytic (two group pre + post)
4 4. Case-control
5 5. Cohort (one group pre + post (before and after))
6 6. Interrupted time series
7 7.Other specify ____________________________
8 8. Can't tell
Was the study described as randomized? If NO, go to Component C.
No Yes
If Yes, was the method of randomization described? (See dictionary)
No Yes
If Yes, was the method appropriate? (See dictionary)
No Yes
8
Provide your explanation:
The study was a random controlled trial because eligible participants were randomly selected into two groups, the intervention group and the control group. The authors describe the study as a “group-randomized cohort design intervention” (Wilson, et al., 2011, p. 464). In addition, the selection of the school was done using “computer generated random numbers” (p. 64). This method was appropriate because randomization minimizes chances of bias “by equalizing other factors that have not been explicitly accounted for in the experimental design” (Vogel, et al., 2010, p. 349). This is because researchers may be tempted to exclude or select subjects who are likely to influence the results in a certain way. By using a computer to generate the random numbers, researcher-bias was eliminated. Nevertheless, the design is not absolutely free of bias because the of the researcher's preconceived knowledge about the target population. In a truly random and objective trial, the researchers should not have foreknowledge of how the intervention will influence the outcome of the study (Edwards & Skinner, 2010). In the present study, the researchers' objectivity may have been compromised by their knowledge that children from low-income neighbourhoods lack better access to recreational facilities such as swimming pools, gyms, and playing grounds. This is especially the case for those living in crowded (slum-like) places. Consequently, their inability to engage in physical activity may not be a function of behaviour (individual choice), by a condition of circumstance. Their home environment cannot favour physical activity, a fact evidenced by their failure to continue engaging in physical activity at two weeks post-intervention. Accordingly, the sampling method was NOT “very appropriate” because the researchers chose a population sample for whom it was fairly easy to predict behaviour change during the intervention period. Specifically, it was clear from the beginning that children from low-income families and minority groups can engage in physical activity given the opportunity. The intervention program offered them the opportunity by creating time for physical activity and providing them with an instructor. In this regard, it is not easy to determine whether the participants engaged in more physical activity as a result of conditioning in light of the Self-Determination and Social Cognitive Theories identified by the researchers, or as a result of the change in circumstances (getting the time and opportunity to engage in physical exercise). If it is the latter, which is also likely, the appropriate intervention is not behavioural conditioning, but simply increasing accessibility to recreational facilities and free time to children from low-income families and minority groups to engage more in physical activities.

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Provide your explanation:
For the purpose of achieving the researchers' objective- encouraging engagement in physical activity among low-income and minority adolescents, the study used the relevant population sample and appropriate sampling technique. The most crucial factor was avoiding bias and making the sample as representative as possible. The study achieved this goal by selecting participants from urban and rural schools serving children from low-income and minority backgrounds (Wilson, et al., 2011, p. 464). Similarly, the researchers measured baseline characteristics to ensure that eligible participants possessed the relevant characteristics (for example did engage in physical activity regularly and were at risk of being overweight or obsess, p. 466). The only weakness of this section is that the researchers had prior knowledge of the likely outcome after the intervention, and therefore the study was more of confirming their predictions rather than “finding out” the effect of an intervention program through a randomized trial.

C) CONFOUNDERS
(Q1) Were there important differences between groups prior to the intervention?
1 1.Yes
2 2. No
3 3. Can't tell
The following are examples of confounders:
1 1. Race
2 2. Sex
3 3. Marital status/family
4 4. Age
5 5. SES (income or class)
6 6. Education
7 7. Health status
8 8. Pre-intervention score on outcome measure
9
Provide your explanation:
The selected sample was diverse in terms of ethnicity, gender, and physical fitness. Fifty-four percent of the participants were female, 73 percent African-Americans, and fifty-one percent were at risk of being overweight or obsess (Wilson, et al., p. 466). This diversity means that some group-specific factors may play a role in the intervention outcome. For instance, domestic responsibilities may deny girls equal opportunity to engage in physical activities as boys. Similarly, differences in physical fitness among the subjects may affect their conditioning/behaviour change rate as those who are overweight may not be as physically active as those who are not. At the same time, the 27 percent whose ethnicity is not stated in the study could be from Caucasian, Asian, or any other ethnic group with more access to recreational facilities than children from African-American families. For example, it is possible that children from Caucasian families may find easy acceptance into group cycles that has access to recreational families, such as friends from rich families. On the other hand, children from low-income African-American families may experience discrimination in public recreational facilities, especially in neighbourhoods where they are a minority. However, other factors like age, economic status and education are the same. The participants were all 6th graders, had a mean age of 11years, and came from low-income background.

(Q2) If yes, indicate the percentage of relevant confounders that were controlled (either in the design (e.g. stratification, matching) or analysis)?
1 1. 80 – 100% (most)
2 2. 60 – 79% (some)
3 3. Less than 60% (few or none)
4 4. Can't Tell
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Provide your explanation:
The researchers checked for potential confounders at baseline level, such as by excluding those with medical conditions that could have interfered with their participation level. Similarly, the researchers used a criterion that eligible subjects had to meet to participate in the intervention program. In addition, the researchers used the Analysis for Covariance (ANCOVA) to measure the relationship among different variable and the degree of their influence across the sample population (Hedeker & Gibbons, 2006, p. 5). This approach ensured that any confounding variables were identified and accounted for when administering the intervention program and in the analysis of the results.

D) BLINDING
(Q1) Was (were) the outcome assessor(s) aware of the intervention or exposure status of participants?
1 1. Yes
2 2. No
3 3. Can't tell
4
Provide your explanation:
The researchers were not trying to investigate an unknown outcome, but measuring the efficacy (effectiveness) of the Active by Choice Today (ACT) trial in increasing physical activity in low-income and minority adolescents. They also used an intervention and control group, which suggest that they were aware of the variables under study. In this regard, the researchers' goal and intention were clear from the outcome, and were aware of the expected outcome. The intervention program was intended to achieve specific and predetermined results; therefore the assessors were aware of the intervention. Similarly, they were aware of the exposure status of the participants because they kept records of progress. In addition, an instructor was employed “a trained team leader with experience in implementing physical activities in youth” (Wilson, et al., 2011, p. 465). The team leader could determine how many hours or minutes of physical activity the intervention group practiced daily, as well as what kind of physical exercise they did. Additionally, observations were used to collect data. This approach ensured that the assessors were constantly monitoring the participants' progress.

(Q2) Were the study participants aware of the research question?
1 1. Yes
1 No
2 3. Can't tell
3
Provide your explanation:
The participants were aware because participation was voluntary. It is expected, accordingly, that the researchers explained the nature of the program and its purpose. At the same time, the participants were encouraged to engage in physical activities ain their home environment (p. 465), and so it was easy to deduce the purpose of the study. Moreover, those who were considered overweight or obsess (85 percent) could have easily inferred the objective of their recruitment into a program that required or encouraged them to engage in regular physical activity.

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