Number needed to screen: Difference between revisions

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imported>Robert Badgett
(New page: The number need to screen is a way of summarizing the benefit of a screening program in health care.<ref name="pmid9685274">{{cite journal |author=Rembold CM |title=...)
 
imported>Joe Quick
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The [[number need to screen]] is a way of summarizing the benefit of a [[mass screening|screening program]] in health care.<ref name="pmid9685274">{{cite journal |author=Rembold CM |title=Number needed to screen: development of a statistic for disease screening |journal=BMJ |volume=317 |issue=7154 |pages=307–12 |year=1998 |pmid=9685274 |doi= |issn=|url=http://www.bmj.com/cgi/content/full/317/7154/307}}</ref>
{{subpages}}
The '''number needed to screen''' is a way of summarizing the benefit of a [[mass screening|screening program]] in health care.<ref name="pmid9685274">{{cite journal |author=Rembold CM |title=Number needed to screen: development of a statistic for disease screening |journal=BMJ |volume=317 |issue=7154 |pages=307–12 |year=1998 |pmid=9685274 |doi= |issn=|url=http://www.bmj.com/cgi/content/full/317/7154/307}}</ref> The calculations are derived from the results of a [[randomized controlled trial]] of a screening program.


{| class="wikitable" align="center"
{| class="wikitable" align="center"
|+ Two-by-two table for an intervention
|+ Two-by-two table for a screening program
!colspan="2" rowspan="2"| || colspan="2"| Outcome||
!colspan="2" rowspan="2"| || colspan="2"| Outcome||
|-
|-
| Present || Absent||
| Present || Absent||
|-
|-
| rowspan="3"|'''Screening''' || Screen group || Cell A|| Cell B||Total in intervention group
| rowspan="3"|'''Screening''' || Screen group || Cell A|| Cell B||Total in screening group
|-
|-
| Control group|| Cell C|| Cell D||Total in control group
| Control group|| Cell C|| Cell D||Total in control group
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:<math>\mbox{Experimental event rate}=\left (\frac{\mbox{Cell A}}{\mbox{Cell A + Cell B}}\right )</math>
:<math>\mbox{Experimental event rate}=\left (\frac{\mbox{Cell A}}{\mbox{Cell A + Cell B}}\right )</math>


:<math>\mbox{Control event rate}=\left (\frac{\mbox{Cell C}}{\mbox{Cell C + CellD}}\right )</math>
:<math>\mbox{Control event rate}=\left (\frac{\mbox{Cell C}}{\mbox{Cell C + Cell D}}\right )</math>


===Measures of efficacy===
===Measures of efficacy===
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:<math>\mbox{Number need to screen}=\left (\frac{100}{\mbox{Absolute risk reduction}}\right )</math>
:<math>\mbox{Number need to screen}=\left (\frac{100}{\mbox{Absolute risk reduction}}\right )</math>
==Example==


==References==
==References==
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==See also==
==See also==
[[Mass screening]]
[[Mass screening]]
[[Category:CZ Live]] [[Category:Health Sciences Workgroup]]

Latest revision as of 01:35, 22 December 2007

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The number needed to screen is a way of summarizing the benefit of a screening program in health care.[1] The calculations are derived from the results of a randomized controlled trial of a screening program.

Two-by-two table for a screening program
Outcome
Present Absent
Screening Screen group Cell A Cell B Total in screening group
Control group Cell C Cell D Total in control group
Total with outcome Total without outcome

Calculations

Event rates

Measures of efficacy

Example

References

See also

Mass screening