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  2. Hazard ratio - Wikipedia

    en.wikipedia.org/wiki/Hazard_ratio

    Hazard ratios do not reflect a time unit of the study. The difference between hazard-based and time-based measures is akin to the difference between the odds of winning a race and the margin of victory. [3] When a study reports one hazard ratio per time period, it is assumed that difference between groups was proportional.

  3. Proportional hazards model - Wikipedia

    en.wikipedia.org/wiki/Proportional_hazards_model

    This interpretation of the baseline hazard as "hazard of a baseline subject" is imperfect, as the covariate being 0 is impossible in this application: a P/E of 0 is meaningless (it means the company's stock price is 0, i.e., they are "dead"). A more appropriate interpretation would be "the hazard when all variables are nil".

  4. Number needed to harm - Wikipedia

    en.wikipedia.org/wiki/Number_needed_to_harm

    Formula Value Absolute risk increase ARI EER − CER: 0.1, or 10% Number needed to harm: NNH 1 / (EER − CER) 10 Relative risk (risk ratio) RR EER / CER: 1.25 Relative risk increase RRI (EER − CER) / CER, or RR − 1 0.25, or 25% Attributable fraction among the exposed: AF e (EER − CER) / EER: 0.2 Odds ratio: OR (EE / EN) / (CE / CN) 1.5

  5. Failure rate - Wikipedia

    en.wikipedia.org/wiki/Failure_rate

    A concept closely-related but different [2] to instantaneous failure rate () is the hazard rate (or hazard function), (). In the many-system case, this is defined as the proportional failure rate of the systems still functioning at time t {\displaystyle t} (as opposed to f ( t ) {\displaystyle f(t)} , which is the expressed as a proportion of ...

  6. Nelson–Aalen estimator - Wikipedia

    en.wikipedia.org/wiki/Nelson–Aalen_estimator

    The Nelson–Aalen estimator is a non-parametric estimator of the cumulative hazard rate function in case of censored data or incomplete data. [1] It is used in survival theory, reliability engineering and life insurance to estimate the cumulative number of expected events. An "event" can be the failure of a non-repairable component, the death ...

  7. Risk matrix - Wikipedia

    en.wikipedia.org/wiki/Risk_matrix

    Risk is the lack of certainty about the outcome of making a particular choice. Statistically, the level of downside risk can be calculated as the product of the probability that harm occurs (e.g., that an accident happens) multiplied by the severity of that harm (i.e., the average amount of harm or more conservatively the maximum credible amount of harm).

  8. Hazard analysis - Wikipedia

    en.wikipedia.org/wiki/Hazard_analysis

    ANSI/GEIA-STD-0010-2009 (Standard Best Practices for System Safety Program Development and Execution) is a demilitarized commercial best practice that uses proven holistic, comprehensive and tailored approaches for hazard prevention, elimination and control. It is centered around the hazard analysis and functional based safety process.

  9. Accelerated failure time model - Wikipedia

    en.wikipedia.org/wiki/Accelerated_failure_time_model

    In full generality, the accelerated failure time model can be specified as [2] (|) = ()where denotes the joint effect of covariates, typically = ⁡ ([+ +]). (Specifying the regression coefficients with a negative sign implies that high values of the covariates increase the survival time, but this is merely a sign convention; without a negative sign, they increase the hazard.)