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  2. Proportional hazards model - Wikipedia

    en.wikipedia.org/wiki/Proportional_hazards_model

    The hazard ratio is the quantity ⁡ (), which is ⁡ = in the above example. From the last calculation above, an interpretation of this is as the ratio of hazards between two "subjects" that have their variables differ by one unit: if P i = P j + 1 {\displaystyle P_{i}=P_{j}+1} , then exp ⁡ ( β 1 ( P i − P j ) = exp ⁡ ( β 1 ( 1 ...

  3. Hazard ratio - Wikipedia

    en.wikipedia.org/wiki/Hazard_ratio

    In survival analysis, the hazard ratio (HR) is the ratio of the hazard rates corresponding to the conditions characterised by two distinct levels of a treatment variable of interest. For example, in a clinical study of a drug, the treated population may die at twice the rate of the control population.

  4. Layers of protection analysis - Wikipedia

    en.wikipedia.org/wiki/Layers_of_protection_analysis

    Layers of protection analysis (LOPA) is a technique for evaluating the hazards, risks and layers of protection associated with a system, such as a chemical process plant. In terms of complexity and rigour LOPA lies between qualitative techniques such as hazard and operability studies (HAZOP) and quantitative techniques such as fault trees and ...

  5. Hazard analysis - Wikipedia

    en.wikipedia.org/wiki/Hazard_analysis

    A hazard analysis is one of many methods that may be used to assess risk. At its core, the process entails describing a system object (such as a person or machine) that intends to conduct some activity.

  6. Discrete-time proportional hazards - Wikipedia

    en.wikipedia.org/wiki/Discrete-time_proportional...

    This approach performs well for certain measures and can approximate arbitrary hazard functions relatively well, while not imposing stringent computational requirements. [5] When the covariates are omitted from the analysis, the maximum likelihood boils down to the Kaplan-Meier estimator of the survivor function. [6]

  7. Factor of safety - Wikipedia

    en.wikipedia.org/wiki/Factor_of_safety

    In engineering, a factor of safety (FoS) or safety factor (SF) expresses how much stronger a system is than it needs to be for an intended load.Safety factors are often calculated using detailed analysis because comprehensive testing is impractical on many projects, such as bridges and buildings, but the structure's ability to carry a load must be determined to a reasonable accuracy.

  8. 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 ...

  9. Job safety analysis - Wikipedia

    en.wikipedia.org/wiki/Job_safety_analysis

    The analysis is subjective to what the role being investigated entails. The headings of the three basic columns are: Job step, hazard and controls. A hazard is any factor that can cause damage to personnel, property or the environment (some companies include loss of production or downtime in the definition as well).