Fundamentals of Clinical Trials Lawrence M Friedman Curt D Furberg David L Demets David M Reboussin And Christopher B Granger

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Lawrence M. Friedman, Curt D. Furberg, David L. DeMets, David M. Reboussin and Christopher B. GrangerFundamentals of Clinical Trials10.1007/978-3-319-18539-2_23

Erratum

Lawrence M. Friedman¹, Curt D. Furberg², David L. DeMets³, David M. Reboussin⁴ and Christopher B. Granger⁵

(1)

North Bethesda, MD, USA

(2)

Division of Public Health Sciences, Wake Forest School of Medicine, Winston-Salem, NC, USA

(3)

Department Biostatistics and Medical Informatics, University of Wisconsin, Madison, WI, USA

(4)

Department of Biostatistics, Wake Forest School of Medicine, Winston-Salem, NC, USA

(5)

Department of Medicine, Duke University, Durham, NC, USA

The updated original online version for this chapter can be found at 10.1007/978-3-319-18539-2_17

In the original publication on page vi, there is a typographical error in the print and online versions of this book. “Principal” was incorrectly spelled as “Principle.”

Corrections to chapter 17, page 381, follow, and these changes have been updated in the book.

Chapter 17

Statistical Methods Used in Interim Monitoring

p 381

Many different spending functions can be specified. The O’Brien–Fleming α ₁(t*) and Pocock α ₂ (t*) type spending functions are specified as follows:

$\begin{array}{ll}{\alpha}_1\left(t^{*}\right)=2-2\Phi \left({Z}_{\alpha / 2}/\sqrt{t^{*}}\right)\hfill & \sim \mathrm{O}'\mathrm{Brien}\hbox{-} \mathrm{Fleming}\hfill \\ {}{\alpha}_2\left(t^{*}\right)=\alpha\ \ln \left(1+\Big(e-1\right)t^{*}\Big)\hfill & \sim \mathrm{Pocock}\hfill \\ {}{\alpha}_3\left(t^{*}\right)=\alpha\ {t^{*}}^{\theta}\hfill & \mathrm{for} \ \theta >0\hfill \end{array}$

The spending function α₃(t*) spends alpha uniformly during the trial for θ = 1, at a rate somewhat between α₁(t*) and α₂(t*). Other spending functions have also been defined [75, 76].

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