PubMed HealthSearch

PubMed · 8511446

Exact conditional and unconditional sample size for pair-matched studies with binary outcome: a practical guide.

Abstract

Tables of sample sizes for pair-matched studies with binary outcome are presented. They are based on conditional and unconditional approaches using the 'exact' (binomial) test. An approximate procedure is suggested to estimate the sample size for parameter values that do not correspond exactly with table entries. The procedure utilizes a minor modification of the large-sample formula given by Connett et al. A practical strategy for estimating the overall sample size in the presence of a nuisance parameter (the proportion of discordant pairs) is recommended. An example from a proposed clinical trial is given.

Explore related subjects

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

P Royston. 1993-04-15. Exact conditional and unconditional sample size for pair-matched studies with binary outcome: a practical guide.. https://doi.org/10.1002/sim.4780120709

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related citations

Improved confidence intervals for the difference between binomial proportions based on paired data.

Existing methods for setting confidence intervals for the difference theta between binomial proportions based on paired data perform inadequately. The asymptotic method can produce limits outside the range of validity. The 'exact' conditional method can yield an interval which is effectively only one-sided. Both these methods also have poor coverage properties. Better methods are described, based on the profile likelihood obtained by conditionally maximizing the proportion of discordant pairs. A refinement (methods 5 and 6) which aligns 1-alpha with an aggregate of tail areas produces appropriate coverage properties. A computationally simpler method based on the score interval for the single proportion also performs well (method 10).

Binomial Distribution

Interval estimation for the difference between independent proportions: comparison of eleven methods.

Several existing unconditional methods for setting confidence intervals for the difference between binomial proportions are evaluated. Computationally simpler methods are prone to a variety of aberrations and poor coverage properties. The closely interrelated methods of Mee and Miettinen and Nurminen perform well but require a computer program. Two new approaches which also avoid aberrations are developed and evaluated. A tail area profile likelihood based method produces the best coverage properties, but is difficult to calculate for large denominators. A method combining Wilson score intervals for the two proportions to be compared also performs well, and is readily implemented irrespective of sample size.

Binomial Distribution

Intrasound vibration in the early diagnosis of scaphoid fracture.

A prospective trial was designed to assess the sensitivity and specificity of intrasound vibration for the early detection of scaphoid fracture. We replicated the method described by Finkenburg et al. (J Hand Surg 1993;18A:4-7) in an attempt to corroborate their results. We found the test to be 73% sensitive and 51% specific. Because the test was not 100% sensitive, as claimed by Finkenburg et al., we discontinued the use of this device in our hospital.

Binomial Distribution