title: Use of the Optimality Index-United States in perinatal clinical research: a validation study.
abstract: The objective of this study was to assess the validity and observed effect size of a new instrument, the Optimality Index-United States (OI-US), for use in perinatal clinical research. Using a large, hospital-based, midwifery service clinical database that included complete obstetric data for 3425 women, we examined discriminant validity and the effects of two different scoring methods used with the OI-US. Discriminant validity was confirmed by comparing OI scores for women who remained low risk and did not require physician involvement in their care (OI score mean = 84%; standard deviation [SD] = 8%) compared to those whose condition changed to require physician involvement in their care (mean = 71%; SD = 10%; P < .001). Two methods of scoring the OI-US were compared, finding no significant difference and suggesting that the types of data available and the research question can drive this decision. Finally, effect size was calculated by two methods: Cohen's d (-1.4) and the effect size correlation (r = -0.548), the latter of which corresponds to a d of -1.3, both resulting in a similarly large effect size estimation. The OI-US is a new instrument that shows promise for use in perinatal clinical research, particularly when assessing more subtle clinical differences in outcomes between study groups.
authors.affiliation: University of Michigan, 400 N Ingalls, Rm 3249, School of Nursing, University of Michigan, Ann Arbor, MI 48109, USA. kanelow@umich.edu
authors.forename: Lisa Kane
authors.initials: LK
authors.lastname: Low
authors.forename: Julia S
authors.initials: JS
authors.lastname: Seng
authors.forename: Janis M
authors.initials: JM
authors.lastname: Miller
mesh_terms: D000328:Adult; D019985:Benchmarking; D015400:Clinical Nursing Research / Q000592:standards*; D019317:Evidence-Based Medicine; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D016389:Maternal-Child Nursing / Q000592:standards*; D008880:Midwifery / Q000592:standards*; D017283:Neonatal Nursing / Q000592:standards; D015403:Nursing Evaluation Research; D017063:Outcome Assessment, Health Care; D018743:Perinatal Care / Q000592:standards; D011247:Pregnancy; D011256:Pregnancy Outcome; D019984:Quality Indicators, Health Care; D011787:Quality of Health Care; D012307:Risk Factors; D014481:United States