Essay Clinical Research Techniques – Effects of a Treatment – Psychology Assignment Help

Assignment Task :

Evidence?based practice is the use of treatments that have been shown to work. This means they have undergone objective evaluation for a particular problem and produced clinically significant effects. This document describes how treatments can be evaluated, which means that it’s about clinical research techniques. 

Psychologists in clinical practice must be research?literate so they can understand and apply knowledge from clinical research. This includes being able to choose the best intervention (therapy) for a client from the available options. It also means being able to make informed judgements about the truth of claims about a therapy (there are a lot of claims about therapies) by looking at the research evidence, and basing their decisions on that, rather than relying on personal judgements or other non?scientific sources of information (although skilled clinical judgment and a client’s preferences are important too). Evidence?based practice is partly about understanding research, but it’s also about having an inquiring mind, asking good questions, and not accepting claims at face value or because they sound good or fit with our world view. 

Evidence?base practice relies on the scientific evaluation of therapies. Scientific evaluation includes the use of randomised controlled trials. Randomised controlled trials are not the only source of research evidence, but are the best source because they allow stronger conclusions about cause and effect. 

Randomised controlled trials (sometimes abbreviated to RCT) have the following features 

• Random allocation to conditions 

• What does the ‘controlled’ part of RCT mean? 

• Control is simply about knowing what caused any observed effects on outcome measures. (Can we be sure it was the therapy itself or are there potential alternative explanations for the improvement?) Control means that extraneous influences are minimised and/or distributed randomly across conditions. This is achieved through random assignment to conditions and ensuring that the different conditions are as similar as possible except for the actual treatment itself (the independent variable) 
• Control sometimes means that control conditions are included (e.g., placebo control or waiting?list control) to help distinguish the effects of a treatment from other possible influences 

Research into the efficacy of clinical interventions: A guide to characteristics of clinical research 

Good quality research is essential for understanding the cause of, and most effective treatments for, clinical disorders. The quality of research on treatment outcomes depends on the manner of participant selection and allocation, the study’s design, treatment 

integrity, the measures that are used, and whether clinical significance is appropriately evaluated. Published studies, and journals themselves, vary enormously in quality. 

Below is a description of features that clinical studies (including randomised controlled trials) can have. Many of them have implications for the quality of the study. Some are more important than others in a particular context. 

This information (and logic) should be used to guide your answer to Assignment 2. 

Selection of participants 

To evaluate a treatment for a particular psychological disorder, obviously research participants need to be people who have the disorder. The existence of the target problem needs to be confirmed (for treatment of a formally diagnosable disorder, participants must meet the diagnostic criteria according to a validated measure). 

• Good clinical studies confirm diagnosis using a structured or semi?structured clinical interview (rather than relying solely on self?report questionnaires). Of course, if the authors do not claim that their sample has a formally diagnosed disorder, then formal diagnostic procedures are not essential. 

• When diagnostic measures require skill to administer and interpret, such as structured clinical interviews, a subset of assessment sessions might be recorded and undergo independent checks for inter?rater reliability. A formal/objective agreement index (extent of agreement among different scorers as to the diagnosis) will be reported. 

• Some studies exclude potential participants with more than one diagnosis (that is, people who have another problem in addition to the target problem). Other studies accept people with certain comorbid disorders but not others (e.g., in studies of anxiety or depression it is common to exclude people with psychosis because psychosis can affect engagement in a psychological therapy). It is common for studies of psychological interventions to accept participants who are taking psychological medications as long as they have been on the medication for a while and their dose is not changed during the study. 

How many participants are needed? 

There is no simple rule about the number of participants. The required number depends on a few considerations, including the following. 

• Having adequate statistical power. Adequate statistical power means having sufficient participants so that inferential statistical tests (like ANOVA or chi?square) are able to detect effects if they exist. No matter how big an effect is, without enough participants, it will be nonsignificant. 

It’s worth noting that, if effects are very small, then the issue of having adequate statistical power is much less important. If effects are small, then the therapy might not be useful even if statistically significant, so we might not care about power. 

• Obviously tiny sample sizes or few remaining participants by the end of a study will restrict the conclusions that can be drawn. For example, if a substantial proportion of participants dropout (withdraw from the study without completing the treatment or measures), we do not know how representative the remaining participants are – did people leave because they were not benefitting? This could bias the final results. 

Study design depends on the research question or purpose 

Randomised controlled trials can be used for several purposes, and the appropriate design depends on the purpose. Examples of common purposes follow. 

• To test the effectiveness of a treatment by comparing it with a control condition of some description (e.g., a placebo control or waiting list control) 

• To test the effects of a relatively new intervention by comparing it with an established treatment 

• To compare two (or more) established treatments to determine if one is better 

• To compare different treatments for groups of participants with different comorbid disorders (e.g., Obsessive Compulsive Disorder alone versus OCD with comorbid Major Depressive Disorder, and OCD with comorbid Panic Disorder)