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  "body": "\n## Summary\n\nAn accelerated failure time model says that covariates stretch or shrink the time scale of a lifetime.\nThe [[survival function|QTM1HZM53Q]] for covariates $x$ is the baseline survival function evaluated at a rescaled time $t e^{-\\beta^T x}$.\nEquivalently, $\\log T$ is a linear function of the covariates plus an error term, so the model is a linear regression for log-times.\nIt is the main alternative to the [[proportional hazards model|N029V3JX60]] in [[survival analysis|443ZWDX88P]]; the Weibull family is the only one that satisfies both.\n\n## Explanations\n\n### L1 human\n\nThe common saying that one dog year equals seven human years is an accelerated failure time idea.\nDogs go through the same life stages as people, only seven times faster.\nIn such a model a treatment does not add a fixed risk; it makes the clock run slower or faster.\nFor example, a coefficient with $e^{\\beta} = 2$ means that every lifetime quantile, such as the median, is doubled.\n",
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