Critical Enquiry into Different Types of Articles

Case-control/non-experimental research;

Non-experimental research is an observational method of study; there is no control or manipulation of the studied variables. (Portney and Watkins, 2009, pg20) Case-control studies are often used to identify factors that may contribute to a medical condition by comparing subjects who have a disorder/illness with patients who do not, but are otherwise similar. The key elements of such studies are that both exposure and outcome have occurred before the start of the study, the period of investigation is backward of the effect to the cause, and the control group is then used to support or refute an inference. (Portney and Watkins, 2009, pg282)

Article one (Striegel-Moore et all, 2007) is an example of these methods. A group of 45 women with a history of BED/BN was formed, using data that had been collected in the 10-year National Heart, Lung, and Blood Institute Growth and Health Study. 1,515 women with no history of said disorders were used as the 'control' group. A range of childhood risk factors for the disorders were explored. Through signal-detection analyses and group comparison, levels of perceived stress were identified as a possible pathway to BN/BED.

Blinded, randomised control trial:

A randomised control trial (RCT) is a study in which participants are randomly allocated to receive one or other of the alternative treatments. There are many different models of an RCT, from simple to most complex. The study can be further rid of observational bias by the 'blinding' method, where study procedures aim to prevent participants and investigators from knowing which intervention was received/which group each subject was assigned to. (Portney and Watkins, 2009, pg170)

In the study for article two (Powell-Tuck et al, 1999), 168 patients were allocated to groups either maintaining a standard feed or those receiving increased glutamine dose. This was done using sealed envelopes, ensuring that the assigning pharmacist wouldn't know which group each patient would be randomly allotted to. The study was therefore carried out as blinded, RCT.

Submitted: Article two:

Powell-Tuck, J Hamieson C P, Bettany, G Obeid, O Fawcett, H Archer, A Murphy, D L 1999, 'Glutamine Supplementation in Parentarel Nutrition', vol 45, issue 2, viewed 6 December 2012, http://gut.bmj.com/content/45/1/82.abstract

Meta-analysis:

Meta-analysis is a method of investigation which focuses on comparing various research findings to identify patterns, sources of disagreement and other connections of interest between the investigations. The main goal is to integrate these findings