Home > Publications . Search All . Browse All . Country . Browse PSC Pubs . PSC Report Series

PSC In The News

RSS Feed icon

Owen-Smith says universities must demonstrate value of higher education

Armstrong says USC's removal of questions from a required Title IX training module may reflect student-administration relations

Fomby finds living with step- or half-siblings linked to higher aggression among 5 year olds

Highlights

PRB training program in policy communication for pre-docs. Application deadline, 2.28.2016

Call for proposals: PSID small grants for research on life course impacts on later life wellbeing

PSC News, fall 2015 now available

Barbara Anderson appointed chair of Census Scientific Advisory Committee

Next Brown Bag

Monday, Feb 1 at noon, 6050 ISR-Thompson
Sarah Miller

Surrogacy assessment using principal stratification when surrogate and outcome measures are multivariate normal

Publication Abstract

Conlon, Anna S., Jeremy M. G. Taylor, and Michael R. Elliott. 2014. "Surrogacy assessment using principal stratification when surrogate and outcome measures are multivariate normal." Biostatistics, 15(2): 266-283.

In clinical trials, a surrogate outcome variable (S) can be measured before the outcome of interest (T) and may provide early information regarding the treatment (Z) effect on T. Using the principal surrogacy framework introduced by Frangakis and Rubin (2002. Principal stratification in causal inference. Biometrics 58, 21-29), we consider an approach that has a causal interpretation and develop a Bayesian estimation strategy for surrogate validation when the joint distribution of potential surrogate and outcome measures is multivariate normal. From the joint conditional distribution of the potential outcomes of T, given the potential outcomes of S, we propose surrogacy validation measures from this model. As the model is not fully identifiable from the data, we propose some reasonable prior distributions and assumptions that can be placed on weakly identified parameters to aid in estimation. We explore the relationship between our surrogacy measures and the surrogacy measures proposed by Prentice (1989. Surrogate endpoints in clinical trials: definition and operational criteria. Statistics in Medicine 8, 431-440). The method is applied to data from a macular degeneration study and an ovarian cancer study.

DOI:10.1093/biostatistics/kxt051 (Full Text)

PMCID: PMC4023321. (Pub Med Central)

Browse | Search : All Pubs | Next