# Generalized Obuchowski-Rockette Methodology for Analysis of Radiologic Diagnostic Imaging Studies

> **NIH NIH R01** · UNIVERSITY OF IOWA · 2021 · $494,355

## Abstract

Project Summary
 Limitations in current statistical analysis methodology for radiologic diagnostic imaging studies greatly
restrict a researcher's choices of study designs and types of analyses. Therefore there is a critical need to cre-
ate a more encompassing multi-reader diagnostic-study analysis methodology that does not limit the ability of
researchers to answer research questions because of strict study-design constraints and few analysis options.
 Our long-term goal is to develop statistical methodology and software appropriate for diagnostic radio-
logical imaging studies that accounts for both patient and reader variability. Our objective here is to further de-
velop Obuchowski-Rockette (OR) methodology (and related Dorfman-Berbaum-Metz) software in a way that
allows for many more types of analyses and study designs. Specifically, we will pursue four specific aims: (1)
Develop a generalized OR methodology that accommodates the same types of designs and analysis models
that can currently be used with conventional analysis-of-variance (ANOVA) and linear regression methodology.
(2) Provide illustrative examples showing how the generalized OR methodology can be applied to situations
where the present OR methodology is not applicable. These include unbalanced designs, regression analyses,
multivariate analyses, ANCOVA analyses, partially-paired-reader data, and missing-cases data. (3) Empirically
validate the OR methodology for each example in Aim 2 through simulations. (4) Develop R, MATLAB and
SAS software code for implementing the generalized OR methodology.
 Expected outcomes include a generalized OR methodology that has the same analysis and design op-
tions as conventional linear regression and ANOVA methodology, in contrast to present OR methodology. The
methodology will apply to any type of reader performance outcome, including ROC, FROC, region-of-interest
(ROI) and location ROC (LROC), with conclusions generalizing to both cases and readers. Other expected
outcomes include illustrative examples of applications of the methodology that were not previously possible, R,
MATLAB and SAS code for implementing the methodology, and a thorough validation of the methodology.
 This research is significant because it will liberate the diagnostic-radiology researcher from the strict
analysis and design limitations of the present methodology, thus enhancing the researcher's ability to assess
the usefulness of imaging modalities and the effects of reader and case attributes on reader performance in an
efficient and meaningful manner. It will be innovative because it will enable new NIH-pertinent horizons that
presently are unattainable because of limited analysis methodology. Presently researchers in diagnostic radi-
ology are greatly constrained in the research questions that they can investigate by the stringent limitations of
the OR (and related DBM) analysis methods. The proposed methodology, by expanding the scope of analyses,
will greatly exp...

## Key facts

- **NIH application ID:** 10172897
- **Project number:** 5R01EB025174-04
- **Recipient organization:** UNIVERSITY OF IOWA
- **Principal Investigator:** Stephen Lawrence Hillis
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2021
- **Award amount:** $494,355
- **Award type:** 5
- **Project period:** 2018-09-01 → 2023-05-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10172897

## Citation

> US National Institutes of Health, RePORTER application 10172897, Generalized Obuchowski-Rockette Methodology for Analysis of Radiologic Diagnostic Imaging Studies (5R01EB025174-04). Retrieved via AI Analytics 2026-05-21 from https://api.ai-analytics.org/grant/nih/10172897. Licensed CC0.

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