Ron D. Hays, Ph.D.

http://twitter.com/RonDHays

The world's most trusted source of subjective
health policy research

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NIH Bio Hays-Biosketch-2009 [PDF] [WORD]
(posted 9/22/09)
Other Support Hays-OS-2008 [PDF] [WORD]
(posted 1/16/09)
Curriculum Vitae Hays-vitae-080109 [PDF] [WORD]
(posted 8/3/09)


                                                                         

Item Response Theory and
Other Psychometric Issues

7/27/2009
Reeve et al. (2007) in Medical Care provided the following guidelines for good fit to
a one-factor model (for evaluation of unidimensionality assumption):

CFA>0.95
RMSEA < 0.06
SRMR < 0.08
Average absolute residual correlation < 0.10


Summary of steps to produce raw score conversion to theta estimates for PROMIS global mental health items   (6/22/2009)
Karen Spritzer with assistance from Ron D. Hays
Summary of steps to produce raw score conversion to theta estimates for PROMIS global physical health items (6/19/2009)
Karen Spritzer with assistance from Ron D. Hays
The authors are eternally grateful to Seung Choi for his expertise and guidance.

6/11/2009
PPV = (sensitivity)(prevalence)/(sensitivity)(prevalence)+(1-specificity)(1-prevalence))
PPV=postive predictive value

NPV=(specificity)(1-prevalence)/(specificity)(1-prevalence)(1-sensitivity)(prevalence))
NPV=negative predictive value