Critical Appraisal, Statistics Problem Example

Background of Issue/Problem:

There is a growing rate of prescriptions for amphetamine used to treat attention deficit disorders. There is a worry that in recent years these drugs are being used more frequently by college students who are not prescribed them. According to the paper, sixteen percent of students using these drugs for medicinal purposes said they had classmates who offered to purchase amphetamines (Ahmann 1999). Another study showed that twenty percent of students had used these drugs without a prescription (Nicholi 1983). The authors of this paper are concerned about this trend, citing a case in which a college student died when mixing these drugs with alcohol.

Purpose of the Study:

With these fears in mind, the authors, K. Graff Low and A.E. Gendaszek, wished to gain knowledge on the usage of amphetamines on college campuses. Since there was a lack of studies on prescription drug abuse in general and amphetamines more specifically, they decided to try and study the motivation of students who use these drugs.

Research Questions and Hypotheses:

The authors were looking to figure out the motivations for illicit prescription drugs versus illegal amphetamines. They saw two possible motivations, improving academic performance and taking this class of drugs recreationally. Academic performance was broken into improved efficiency and general increased performance. Their hypothesis was that recreational users would be willing to use illegal and prescription drugs while those who were seeking improved academic performance would primarily use only prescription drugs.

Methods:

The study was set at an unnamed college in the Eastern United States described as a small, competitive, liberal arts school. One hundred and sixty questionnaires were sent out, with one hundred-fifty being returned. The students were picked from undergraduate psychology classes and were almost perfect split between men and women. The questionnaire responses were kept anonymous. They were separated amongst those who were and were not prescribed any sort of amphetamines. The questions asked about frequency of usage and motivation. The motivation question was judged on two subjective scales frequently used in past surveys of this nature.

Measures:

Findings:

The researchers found that ten percent of the sample had been prescribed amphetamines for medicinal purposes. They did not categorize any of the prescription amphetamine usage amongst this group as abuse. Excluding this group, there was left ninety percent of the sample that could be categorized as abusive users depending on the illicit prescription usage. Amongst them 35.3% admitted to using amphetamines. Ten percent admitted to weekly usage while eight percent claimed weekly usage. The paper does not mention the other eighty two percent, meaning they must use at some other frequency that is less than monthly. They cited three main motivations for this use: improved academic performance, increased efficiency, and recreational use when combined with alcohol. The percentages citing these reasons were 23.3%, 22.0%, and 19.3% respectively. Other motivations mentioned in the paper include as an aid to exercise and also as a weight loss stimulant or for the purpose of repressing appetite. No percentages were given for these motivators.

The study also looked at the usage of illegal amphetamines that cannot be obtained with a prescription. Thirty four percent of those surveyed admitted to using these. Eighty eight percent of those reported Methylenedioxymethamphetamine usage, usually known as MDMA. The other stimulant with widely reported usage was cocaine. Most of these users reported that their frequency of usage was monthly. Males in the survey asserted a higher usage rate of illegal stimulants, just as they had done in regards to prescription amphetamines.

After delivering these basic answers, the authors delivered analysis of them to further assert the validity of any findings. When comparing men and women in both illegal and prescription amphetamine usage, the men’s increase usage rates had t scores of 4.4 and 3.9 respectively. These t scores combined with the large sample size meant that these differences both had p values below one one-hundredth of a percent. Therefore it is very safe to conclude that amongst the population this sample represents, men use both legal and illegal amphetamines more often than women. Illegal stimulant usage and illicit prescription usage were highly correlated together with an r value of .83. Valid, medicinal usage was also correlated with illegal amphetamine use, although not nearly to the same extent with an r of .19.

In regards to the initial hypothesis regarding motivations for usage of both classes of amphetamines, the authors provided some analysis of their findings. There was a significant effect between prescription usage and sensation seeking or recreational usage. However, the effect between academic motivations and prescription usage was not significant. Perhaps unsurprisingly the highest rate of usage was amongst those who reported both motivations for use.

This study shows potential reasons for concern about amphetamine usage amongst college students. It also quite conclusively indicates that males are more likely to abuse these drugs than females. Their hypothesis that illegal drug usage would not be related to any attempts at improving academic performance was shown to be true. However, perfectionism was not associated with illicit usage of the prescription drugs in question as had been hypothesized.

Critical Appraisal

Sample:

The paper states that the study was conducted primarily amongst white middle class students. While this is likely representative of private liberal arts schools, to extrapolate the results to all college students could cause problems. Therefore before making conclusions about college students in general, schools with more diversity, such as public universities, should also be surveyed. The study was also conducted primarily amongst students in psychology courses, which may not have given them a representative sample of the entire student population. Further studies should try to draw from a broader range of courses to get a better cross sampling of all students at the university. Also, there were some surveys not returned. While the rate of return was good, it is possible that those who did not fill it out significantly differed from those that did.

Measures:

The nominal categories for frequency were not extensive enough. When over eighty percent of the responses are listed as “other” there should be more categories for responses. With the reliance on nominal data, a ratio measurement of usage would have been beneficial although difficult to compile through a subjective questionnaire.

Statistical Analyses:

The tests performed were appropriate. A t test for different mean values was used to analyze whether or not the genders differed on amphetamine usage. The correlation between motivations and usage was given in r values. Although it should be noted the authors did not mention what type of correlation analysis was used in this case in regards to the qualitative nature of the data.

Verbal and Visual Presentation:

The statistical tests shown were largely presented well.They all featured p values, and t or f scores. When applicable the degrees of freedom used were given allowing readers to verify the values given themselves. There were a few issues in this area though. In regards to the test without significant findings, that linking academic motivations and illicit prescription usage, power was not discussed. Also one of the main hypotheses was never directly answered with the reader left to figure it out on their own. The one graph in the paper simply reiterates data already given in the text. However, there still is some value to providing a visual.

Potential Bias:

There are problems with the sample that were previously discussed. It should be noted that the paper authors acknowledge these limitations. Considering that this was the first study into this area, these limitations do not stop the study from being worthy of conduction. It represents a good first look at the problem and can be further researched by studies that rectify these limits. Another issue may be not looking into the usage of those with prescriptions. It is possible that some of them are using more than required or that their prescriptions were fraudulently acquired. Some type of study into their usage would likely be informative. Finally, the method of acquiring the information could lead to bias. Subjective reporting could lead to dishonest answers or incorrect answers the responder believes to be correct.