Faculty of Health and Life Sciences
Mental Health Nursing Diploma
September 2009 Cohort
Describe the key issues surrounding reliability, validity and trustworthiness as applied to Evidence Based Practice
The findings from good, current, reliable, valid or trustworthy research are the basis for maintaining high standards of care and all nurses must practice based on the most up to date evidence (NMC 2008). It is now an important part of nursing to actively participate in research and evidence based practice in order to continually improve the standard of the health care system. This process ensures that nurses are kept up to date with relevant information needed to provide the most effective care for patients. In this essay I will base my research within the realms of mental health nursing which is my area of professional practice. Furthermore I will explain some of the key issues surrounding reliability, validity and trustworthiness, all terms of which will be defined. I will then relate these issues to how they are applied in mental health nursing practice by referring to existing research. In order to fully explore the findings of the research I will use studies from both a qualitative and quantitative perspective. The European Commission states that ‘qualitative studies investigate in-depth the motivations, the feelings, the reactions of selected social groups towards a given subject or concept, by listening and analysing their way of expressing themselves in discussion groups or with non-directive interviews.’ This is largely different to information that is obtained in a quantitative study. Market Research World states that ‘quantitative research is used to measure how many people feel, think or act in a particular way. These surveys tend to include large samples. Structured questionnaires are usually used incorporating mainly closed questions - questions with set responses.’ However even though both types of research are helpful in obtaining the required information, it is essential that all studies carried out must demonstrate reliability, validity and trustworthiness. These terms can be described as research measurements. Reliability is one of the most critical concepts when researching. Your work may be based on qualitative and/or quantitative research however your instrument can not be considered valid without being reliable, however it can be reliable without being valid. (Didnon, 2009) For something to be reliable it has to be consistent in its result unless the variable changes. There are three main frames of testing reliability. Firstly there is Inter-rater reliability which is mainly used in mental health. Here, a group of researchers share results that they have obtained from the same topic and a consensus is produced. Secondly, there is the re-test which is considered a popular indicator of reliability (statistics glossary). Here, the same instrument is used over a time frame in which the predicted result is expected to be similar or the same. It is worth mentioning that the reliability here is determined by the strength of the correlation. To avoid the danger of ‘practice effect’ the period of time between tests should be adequate so as to avoid any changes that could affect the reliability.
The third frame test used is ‘split in half’. This is commonly used for quantitative measure (Statistics Glossary) and is similar to the re-test as there is testing over two periods of time; however by changing the wording and order of the questions it can relieve the problem of ‘practice effect’. For a study to be reliable it should show internal consistency. The same variable should be used so as to highlight a consistent correlation in response.
When constructing a study you must be sure it can be considered valid. ‘A measure is valid if it measures correctly and accurately what it is intended to measure’ (Macnee 2004). There are four types of validity which can ensure the...
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