historical control group


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historical control group

In a research study, a person or group of persons who were treated in the past and who provide contrast and comparison to participants currently being studied. Because a wide variety of variables may change over time, the use of historical controls as opposed to a contemporary control group is often an indication that an investigation has less methodological rigor.
See also: group
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0 to calculate independent samples nonparametric t tests (Mann-Whitney U), we examined mean differences between the FWPE/OTS scores of the historical control group and the simulation group.
5%) of the rates of rebleeding between the patients in this study (1/30) and the first historical control group [comprising 80 patients with hyphema treated with oral placebo at our department (26/80)] demonstrated statistically significant differences.
11 The current study evaluated its effectiveness on 188 newborns with severe indirect hyperbilirubinaemia and compared it to a historical control group consisting of 177 neonates treated with conventional phototherapy.
The study compared the outcomes of trials for the same treatments and found that 79% of clinical trials with a historical control group showed a benefit over control, while only 20% of trials with a direct control group showed a benefit over control.
This study examines the rate of late-preterm birth in a hypnosis group (directed to all women) and a historical control group.
Also, comparison of mortality with a historical control group is biased, as general treatment of ARDS has changed substantially in the last decade.

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