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Several studies have examined the benefits and costs of drug treatment; however, they have typically focused on the benefits and costs of a single treatment episode. Although beneficial for certain analyses, the results are limited because they implicitly treat drug abuse as an acute problem that can be treated in one episode. We developed a Monte Carlo simulation model that incorporates the chronic nature of drug abuse. Our model represents the progression of individuals from the general population aged 18-60 with respect to their heroin use, treatment for heroin use, criminal behavior, employment, and health care use. We also present three model scenarios representing an increase in the probability of going to treatment, an increase in the treatment length of stay, and a scenario in which drug treatment is not available to evaluate how changes in treatment parameters affect model results. We find that the benefit-cost ratio of treatment from our lifetime model (37.72) exceeds the benefit-cost ratio from a static model (4.86). The model provides a rich characterization of the dynamics of heroin use and captures the notion of heroin use as a chronic recurring condition. Similar models can be developed for other chronic diseases, such as diabetes, mental illness, or cardiovascular disease.

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We introduce a new method for retrieving formaldehyde (HCHO) based on principal component analysis (PCA) of satellite‐measured radiances. Applying the technique to the Suomi National Polar‐orbiting Partnership/Ozone Mapping and Profiler Suite (S‐NPP/OMPS) radiances between 328.5 and 356.5 nm, we extract principal components (PCs) associated with various physical processes (e.g., ozone absorption and rotational Raman scattering) and measurement details (e.g., wavelength shift). These PCs, along with precomputed HCHO Jacobians, are utilized in spectral fitting to estimate HCHO loading and reduce interferences. Comparisons with model simulations and independent Ozone Monitoring Instrument (OMI) retrievals indicate that our algorithm can detect enhanced HCHO signals over source regions such as the southeast U.S., producing HCHO total columns with similar spatial distributions and seasonal patterns. While our OMPS retrievals are ~15–20% lower than OMI retrievals from a different algorithm, the differences may be attributed to several instrumental and algorithmic factors. This study demonstrates the potential of PCA algorithms and of OMPS for continuing the long‐term satellite HCHO data record.