NIOSH Radiation Dose Reconstruction 

Program

Ten-year Program Review:

Quality of Science – Phase I Report

Robert Daniels

and 

Henry Spitz

May 2011

St. Louis, MO
Purpose

• 2010: NIOSH initiates 10 Year Program Review of DR

– Committed to highest quality of science in its programs 

– Recognizes the importance of program transparency and 

responsiveness to the needs and concerns of 

stakeholders

• The quality of science is identified as a critical 

program element for review

– Many questions on exposure proxies in dose 

reconstruction (DR) → Focus on indirect exposure 

assessment (IEA) methods
Background

• NIOSH is charged with providing “reasonable” estimates of 

radiation doses to covered employees seeking compensation 

under EEOICPA

– Reasonable estimates are well-based in science, timely, and fair

– NIOSH Dose Reconstruction (DR)

• NIOSH evaluates the completeness and adequacy of 

individual monitoring data and provides remedies for 

information gaps (42 CFR 82, §82.15)

– Indirect exposure assessment (IEA) methods are commonly used to 

fill data gaps
Review Scope and Conduct

• Scope: Coworker and surrogate data use

– "surrogate data" is exposure information from facilities other than 

that employing the covered worker

– "coworker" models use exposure data from similar workers 

(i.e., comparable exposure risks) 

• Two reviewers, working independently:

– One focusing on issues related to coworker models

– One examining the use of surrogate data

• Review: Internal, peer, and stakeholder (ongoing)
Report Structure

• General program area on IEA

– Scientific basis

– Documentation quality

– Peer and stakeholder review

• External radiation coworker analyses

– Review of scientific method

– K25 coworker model replication

• Public comment

• Summary of findings and recommendations

• Appendix on surrogate data
General Findings: Accomplishments

• Completed 24,000 dose reconstructions

• Several advancements in retrospective exposure assessment 

• Gathered and organized a wealth of information on U.S. 

Atomic Weapons Workers

• Developed and “published” over 100 technical documents 

on dose reconstruction
General Findings: Authority

• Epi studies rarely benefit from complete exposure 

information

– Like DR, Epi studies have often relied on exposure proxies

• Epi research provides a firm foundation for coworker models 

and other surrogate information in NIOSH DR

– The use of information from coworkers is clearly authorized under 

the rule [42 CFR 82, §82.17(a)]

– The use of surrogate data is an acceptable scientific approach 

provided that the data complement, but not supplant, information 

from preferred sources
General Findings: Documentation

• DR documents are a layered structure of policies, plans, 

procedures, implementation guides, technical information 

bulletins, and technical basis documents

• Systems available to standardize nomenclature, format, and 

uniquely identify documents; however, content varied 

markedly between documents

• All documents are internally reviewed prior to issuance but 

periodic or external reviews are not required 

• Although touted as “living documents,” revision appears 

infrequent in most cases
General Findings: Methods

• DR uses a graded-approach that balances precision and 

accuracy (science) with fairness and efficiency 

(responsiveness)

– Claimant-favorable bias is preferred

– Claimant-favorability is implied but rarely quantified 

• Better assessment of bias may greatly improve confidence in 

the program and reinforce assertions of claimant-favorability

– Biases (in either dose direction) may play a large role in an 

individual’s compensation decision
Specific Findings and 

Recommendations

• Emphasis on program improvements in areas of 

documentation, peer review, and validation of 

exposure assessment methods

– Documentation (2)

– Peer and stakeholder review (2)

– Validation (7)
Documentation

• Findings: 

– Overall, the system provided documents that were clear, 

concise, and relevant to the points of use

– Some errors and inconsistencies noted

• Document quality varies by authorship

• Control of cross-referenced or layered documents was lacking
Documentation—cont. 

• Findings: 

– Revisions lacked timeliness and, in some instances, appeared 

unresponsive to concerns raised in previous reviews

• Revisions slowed by the deliberate manner in which 

science issues are resolved between the ABRWH and DCAS 

• Revisions can trigger a re-evaluation of DRs regardless of 

the effect (if any) on dose estimates

– Delay of minor revisions until more substantive changes are 

indicated

• Many documents have not been evaluated since first 

issued 
Documentation—cont. 

• Recommendations:

– Recognize interrelationships between documents and 

avoid transfers of technical inaccuracies

– Include periodic reviews by subject matter experts to 

systematically and expeditiously uncover inconsistent 

and erroneous text

– Avoid delays in correcting technical inaccuracies

• Develop/improve methods to initiate, track, and finalize 

document revisions in a timely manner
Document Review

• Findings:

– External reviews by scientific peers and stakeholders are 

not required

– Documentation has benefitted greatly from ABRWH 

review, although many documents have not yet been 

reviewed

– Information is inconsistently sought from stakeholders 

and only after initial publication

• Avoidable inaccuracies are identified after publication

– Weakly defined process for comment resolution
Document External review 

• Recommendations:

– Seek external peer review on science documents that 

have not been reviewed by the ABRWH 

– Expand reviews to systematically solicit input from peers 

and stakeholders on important scientific issues prior to 

publication

– Conduct and record comment resolution in a manner that 

promotes continued solicitation and consideration of 

input from scientists, affected workers, and worker 

advocates
Methods

• Finding:

– Dose estimates from independent modeling were 

comparable but, on average, < DCAS results

• Model is reproducible

• Supports claimant favorability

– Some models lacked information on source data, 

assumptions, statistical methods, and limitations

– Validation was inconsistent or absent from some models

– Rigorous validation is especially important for “bounding” 

estimates that rely on models that may poorly describe outlying 

regions of dose distributions
Methods Improvement

• Recommendations:

– Systematically assess the validity of estimates obtained from 

current models 

• Examine and quantify coverage, anomalies, and limitations 

in data selected for coworker analyses

• Examine between- and within-worker variance 

components in current coworker models

• Consider additional strata (exposure determinants) in 

current models

• Use well-defined “gold-standards” for comparisons

• Quantify the degree in which claimant-favorability is 

achieved (i.e., estimate the bias)
Stakeholder Issues

• Dose reconstruction is a lengthy and complicated 

process

– In the absence of information on true dose, judgments 

were made that potentially bias decisions in a claimantadverse manner

• Commenters were wary of differences in facilities 

and jobs that may be inadequately addressed in 

current models using coworker or surrogate data