FAQs: Probability of Causation (POC)
The Department of Labor (DOL) is responsible for determining the probability that a cancer included in a claim under EEOICPA (The Act) was caused by workers’ exposure to radiation during nuclear weapons production. DOL will determine the “probability of causation” for each claim for which NIOSH is required to complete a dose reconstruction. Generally, with some exceptions, these claims are for workers who are not a member of the Special Exposure Cohort.
To find answers to your questions about Probability of Causation, click any one of the questions listed below to view its answer.
Probability of Causation
Under EEOICPA (The Act), probability of causation is a measure of how likely it is that an energy employee’s cancer was “at least as likely as not” caused by occupational exposure to ionizing radiation.
The Department of Labor (DOL) will use the energy employee’s personal characteristics, employment, medical information, and dose reconstruction results developed by NIOSH to determine the probability of causation.
This rule provides the guidelines that DOL uses to determine the degree of likelihood that a cancer included in a case was “at least as likely as not” caused by the energy employee’s exposure to radiation during nuclear weapons production.
A copy of the Probability of Causation rule can be found on our website on The Act page.
NIOSH developed a computer program that is used by DOL to determine the probability of causation. The computer program, known as NIOSH-IREP, uses cancer risk models developed primarily by the National Cancer Institute (NCI) to estimate the probability of causation under The Act.
The risk models take into account the energy employee’s cancer type, year of birth, year of cancer diagnosis, exposure information (years of exposure, radiation type, and dose). Smoking history is taken into account for lung cancer cases. Ethnicity is taken into account for skin cancer cases. Under Part B of the Act, exposures to other occupational, environmental, or dietary carcinogens are not currently taken into consideration for the probability of causation calculation.
Probability of causation is expressed as a percentage between 0 and 100. A value of 100% means that it is certain that the radiation dose was the cause of the cancer. A value of 0% means that it is certain that the radiation dose was not the cause of the cancer. As defined in The Act, probability of causation values greater than or equal to 50% at the upper 99th percentile credibility limit mean that it is “at least as likely as not” that the radiation dose caused the energy employee’s cancer. Therefore, if the probability of causation for your case is less than 50%, you will not be entitled to compensation. If your probability of causation is between 50% or greater, DOL will recommend that you receive compensation.
No, NIOSH reconstructs a worker’s radiation dose and determines a final estimate of the worker’s exposure to radiation. The results from a worker’s dose reconstruction are sent to DOL. DOL determines the probability of causation – the likelihood that the worker’s cancer was related to radiation exposure received while employed at a covered facility.
A term used to describe the lack of precision and accuracy of a given estimate, the extent of which depends upon the amount and quality of the evidence or data available.
Some statistical issues associated with epidemiological studies (e.g., possible measurement error, possible effects of confounding variables, etc) are:
- Amount of radiation exposure
- Dose-response assumptions
- Transfer of “excess risk” from Japanese and other exposed populations to EEOICPA claimant population
- Uncertainty is built into nearly every part of the process of estimating causation
- Uncertainty distributions are used in dose reconstruction, cancer risk models, etc.
- “Credibility limits” are placed around the central estimate of PC
- Upper 99th percentile determines final PC result and claim outcome
- An accounting of uncertainty is necessary because the upper 99% credibility limit of PC is used in adjudicating claims for compensation
- Uncertainty is often a major contributor to PC
A range of discrete or continuous values arrayed to encompass, with high confidence, the true but unknown values of a given quantity or parameter.
The Upper 99th percent credibility limit is the 99th percentile of the range of values in an uncertainty distribution. The uncertainty distribution of the probability of causation (PC) is first estimated, and the upper 99th percentile of this distribution is compared to the decision criterion (a PC of 50%) to determine eligibility for compensation.
- NIOSH-IREP includes a procedure to calculate an upper 99% credibility limit of PC when a claim for compensation involves more than one primary cancer.
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In all these cases, NIOSH-IREP is run for each primary cancer separately, and the upper 99% credibility limit of probability of causation (PC) for all cancers combined is computed based on the upper 99% credibility limits of all the cancers involved, using the Multiple Cancer Equation:
PCtotal = 1 – [(1 – PC1)x(1 – PC2)x…x(1 – PCn)]
If you have additional questions about probability of causation, please contact us in one of the following ways:
Mail:
Department of Health and Human Services
National Institute for Occupational Safety and Health (NIOSH)
Robert A. Taft Laboratories, MS-C45
1090 Tusculum Avenue
Cincinnati, OH 45226
Phone:
Toll-free: 1-877-222-7570
E-mail: