Validity and accuracy - Revision history

Bosmana fem at 19:25, 29 March 2023

2023-03-29T19:25:39Z

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	The sensitivity of a diagnostic test measures the proportion of those people who have the disease and are correctly detected by the test (test positive). The sensitivity of a test can only be measured among those for whom the diagnosis has already been confirmed by other means than the test under study.		The sensitivity of a diagnostic test measures the proportion of those people who have the disease and are correctly detected by the test (test positive). The sensitivity of a test can only be measured among those for whom the diagnosis has already been confirmed by other means than the test under study.

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	The specificity of a diagnostic test is the proportion of those people who do not have the disease and are correctly left undetected by the test (test negative). The specificity of a test can only be measured among those for whom the diagnosis has already been confirmed by other means than the test under study.		The specificity of a diagnostic test is the proportion of those people who do not have the disease and are correctly left undetected by the test (test negative). The specificity of a test can only be measured among those for whom the diagnosis has already been confirmed by other means than the test under study.
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	The positive predictive value (PPV) of a diagnostic test is the proportion of those testing positive and truly have the disease. The higher the positive predictive value, the higher the likelihood that a person tested positive truly has the disease. The PPV is high when the specificity is high. A high prevalence of the disease or condition tested for in the population increases the PPV.		The positive predictive value (PPV) of a diagnostic test is the proportion of those testing positive and truly have the disease. The higher the positive predictive value, the higher the likelihood that a person tested positive truly has the disease. The PPV is high when the specificity is high. A high prevalence of the disease or condition tested for in the population increases the PPV.

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	1. Sheringham J, Kalim K, Crayford T. Mastering Public Health: A guide to examinations and revalidation. ISBN-13 978-1-85315-781-3.		1. Sheringham J, Kalim K, Crayford T. Mastering Public Health: A guide to examinations and revalidation. ISBN-13 978-1-85315-781-3.


			==FEM PAGE CONTRIBUTORS 2007==
			;Editor
			:Maarten Hoek
			;Original Authors
			:Julia Fitzner
			:Alain Moren
			;Contributors
			:Lisa Lazareck
			:Arnold Bosman
			:Maarten Hoek


	[[Category:Testing the Tests]]		[[Category:Testing the Tests]]

Bosmana fem at 19:23, 29 March 2023

2023-03-29T19:23:56Z

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Bosmana fem at 19:10, 29 March 2023

2023-03-29T19:10:02Z

← Older revision		Revision as of 19:10, 29 March 2023
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			==Validity==
			Validity describes whether the results of an experiment really do measure the concept being tested. In other words, it says something about the experiment (or study, or surveillance system) as a whole; the design, methods and tests included. If the design or the choice of methods is inappropriate in relation to the aim of the experiment, then the results will be considered not valid, even when the tests used have produced accurate measurements. Likewise, if the design and methods of s study have been chosen appropriately (regarding the aim of the study), then the validity of the results will be mostly determined by the accuracy of the tests used. Therefore the rest of this article will focus in more detail on the concept of accuracy.

			Consistency in the production of good results requires a standardized operating procedure that includes quality assurance, quality control, and quality assessment [1].

			==Accuracy==
			The accuracy (performance) of a diagnostic test is expressed in four dimensions (sensitivity, specificity, positive predictive value and negative predictive value), The prevalence of the disease or condition tested for affects some - but not all - of the test performance characteristics [1].

			{\| class="wikitable" style="font-style:italic; font-weight:bold; text-align:center; vertical-align:middle;"
			\|- style="font-style:normal; font-weight:normal; text-align:left; vertical-align:bottom;"
			!
			! style="font-weight:bold;" \|
			! colspan="2" style="text-align:center;" \| <br /> Does the person truly have the condition?
			!
			\|- style="font-style:normal; font-weight:normal;"
			\| style="vertical-align:bottom; text-align:left;" \|
			\| style="vertical-align:bottom; text-align:left;" \|
			\| style="font-weight:bold;" \| YES
			\| style="font-weight:bold;" \| NO
			\|
			\|-
			\| rowspan="2" style="font-style:normal; font-weight:normal; text-align:left;" \| Test result
			\| style="vertical-align:bottom; font-style:normal; text-align:left;" \| Positive
			\| A (true positive)
			\| B (false positive)
			\| A + B
			\|-
			\| style="vertical-align:bottom; font-style:normal; text-align:left;" \| Negative
			\| C (false negative)
			\| D (true negative
			\| C + D
			\|-
			\| style="vertical-align:bottom; font-style:normal; text-align:left;" \|
			\| style="vertical-align:bottom; font-style:normal; font-weight:normal; text-align:left;" \|
			\| A + C
			\| B + D
			\| A + B + C + D
			\|}

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			The sensitivity of a diagnostic test measures the proportion of those people who have the disease and are correctly detected by the test (test positive). The sensitivity of a test can only be measured among those for whom the diagnosis has already been confirmed by other means than the test under study.

	[[Category:Testing the Tests]]		[[Category:Testing the Tests]]

Bosmana fem: Created page with " Category:Testing the Tests"

2023-03-22T21:36:18Z

Created page with " Category:Testing the Tests"

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[[Category:Testing the Tests]]