When comparing the full sample prior to propensity score matching, a greater fraction of post-Prop 47 arrest events had concurrent arrests of other types , suggesting a decline in arrests when drug possession was the sole offense. Post-Prop 47 arrestees also appeared to differ in terms of criminal histories, with more prior arrests . The propensity score matched sample had better covariate balance. For sale/transport arrests, pre and post groups were much more similar . Though they were not compared statistically, we find the population arrested for these offenses appears quite different from those arrested for Prop 47 drug offenses. Prop 47 offenders had more numerous but lower level prior arrests and convictions. Racial differences were notable as well, with larger racial disparities among sale/transport arrests .With regard to Prop 47 arrests, pre and post estimates for each county suggest counties where felony convictions were more likely pre-Prop 47 were reduced towards zero to a greater degree, such that post-Prop 47 outcomes were more similar across counties. Mixed models with random pre-Prop 47 intercepts, random coefficients for the policy effect, and an unstructured covariance structure allowing for a correlation between intercept and slope random effects, showed a significant, negative covariance between random effects . Aligning with the pattern depicted in Figure 3.2, this suggests counties where felony convictions were more likely in the pre-period also declined more towards the less punitive counties, reducing the variance across counties. The reduction in county differences is corroborated by variance estimates from models with county specific random intercepts for the pre and post periods . The likelihood ratio test comparing an exchangeable covariance structure as a nested model indicated that the unstructured covariance structures which allowed pre- and post-Prop intercept variances to differ,vertical aeroponics farming was a better fit to the data . To put this in concrete terms, of the 56 California counties, prior to the policy the most punitive county had a conviction probability of .38 , whereas the least punitive county had a conviction probability of .04 .
After Prop 47 was adopted, the most punitive county had a conviction probability of .19 whereas the least punitive county had a conviction probability of .02 . Another way to conceptualize these results is in terms of how discrepant the statewide probability of felony conviction was from the least punitive county pre-Prop 47, and the extent to which that discrepancy changed post-Prop 47. Prior to Prop 47, the statewide probability of felony conviction was 17 percentage points higher than the least punitive county , meaning 81% of statewide felony convictions following Prop 47 drug arrests would not have occurred if prosecuted in the least punitive county. Whereas after Prop 47, the statewide probability was just 3 percentage points higher than the least punitive county prior to passage . There was also significant variation across counties in the likelihood of felony conviction following a sale/transport arrest , ranging from 0.05 in Merced County to 0.51 in Calaveras County in the pre-Prop 47 period. However, mixed model results indicated the significant variance in the pre-Prop 47 period , did not decline post-Prop 47 . This suggests that, while people arrested for sale/transport were less likely to ultimately get a felony conviction after Prop 47 was adopted, this effect did not vary substantially across counties, and no county showed an increase in felony conviction probability for sale/transport arrests. In other words, it does not appear that more punitive counties altered plea bargaining practices for sale/transport arrests to retain pre-Prop 47 levels of felony convictions, as this would have resulted in an increase in variance in felony conviction probabilities for this category of arrest. Findings aligned with sensitivity analyses that assumed all cases with missing dispositions received felony convictions .In this study of the change in felony convictions in California counties after Proposition 47 reduced criminal penalties for drug possession, we found significant declines in the likelihood of a felony conviction following arrests for Prop 47 drug offenses and non-Prop 47 felony drug offenses . Prior to Prop 47, dramatic geographic inequalities in probability of felony convictions after drug possession arrests prevailed between counties, and these geographic inequalities were substantially reduced after adoption of Prop 47.
The reduction in felony convictions aligns with reports from the Judicial Council of California on reductions in felony filings following Prop 47 passage , while providing new evidence that reductions led to declines in geographic disparities in felony convictions for drug arrests. By holding county-specific case characteristics constant across time, this study identified a reduction in the excess variation that was attributable to county practices. This impact likely reflects that Prop 47 eliminated prosecutorial discretion for how drug possession can be charged. While previous research has found that the county-specific interpretation and implementation of reforms tends to reinforce the preexisting prosecution and sentencing practices within the county , results from the current study do not indicate counties attempted to mitigate the effects of Prop 47 with felony filings for concurrent offenses, or reducing plea bargaining for sale offenses. Several factors could explain why Prop 47 led to reductions in geographic disparities in case outcomes, when other reforms have not. Prop 47 was a voter initiative, and considering the influence of community priorities for law enforcement on charging policies and decisions, prosecution practices may be more responsive to these types of reforms. Secondly, Prop 47 called for reduced criminal penalties, whereas prior studies have evaluated reforms like three strikes laws which maximize punishment. Maximizing punishment is costly, whereas reducing it can assuage overburdened courts. Therefore, we may be more likely to see change resulting from reforms that call for lesser criminal penalties, and especially when that call comes from the public. Reducing variation in the likelihood of a felony conviction for two equivalent cases mitigates inequalities in criminal justice exposure due to unequal applications of the law. However, requiring that all drug possession offenses be prosecuted as misdemeanors also suggests that cases with different characteristics are now being treated more similarly. A defendant can still be convicted of a felony for concurrent felony offenses, so it is the effect of criminal history on case outcomes which we would expect to be minimized post-Prop 47. Criminal history is strongly associated with race/ethnicity, which may reflect biases and practices in drug law enforcement , while increasing the severity of punishment for subsequent drug offenses .
There is evidence Prop 47 in fact reduced the effect of criminal histories in San Francisco, where prior to Prop 47, racial disparities in case dispositions and sentencing were attributable to more extensive pretrial detention and criminal histories among black defendants . When Prop 47 reclassified drug possession offenses to misdemeanors, these characteristics had lesser effects on case outcomes, and racial disparities declined. Further research could assess whether findings from San Francisco apply statewide. There are also implications for substance use disorder treatment. Prop 47 generated $103 million in savings in the first year, awarded through grants to counties to increase access to substance use disorder and mental health treatment, and education . Counties with few felony convictions pre-Prop 47 may have had greater support for and availability of drug diversion options which allow dismissal of charges for successful drug treatment completion. However, Prop 47 generated concerns that without the possibility of a felony conviction, the incentive to engage in treatment would be removed . Prior research has suggested that,vertical cannabis farm as compared to volitional substance users, individuals with more severe substance use disorders tend to fail to meet the court’s conditions for diversion and ultimately receive harsher termination sentences . If this were the case, it would be logical that this group would opt out of diversion options now that the sentence for drug possession is less severe. Whether this is the case, and if so, understanding successful strategies counties have developed to increase access to needed treatment through other routes, would be valuable. CA DOJ’s Statewide Automated Criminal History System data is the most comprehensive data source available for studying criminal justice policy changes in the state, and has been used in significant studies of Prop 47, as well as other reforms such as Prop-36, which increased drug diversion following arrest . While the use of ACHS to capture the outcomes of all arrests in the state is a strength of this study, ACHS also faces the quality challenges typical of large administrative datasets, as CA DOJ must rely upon consistent and timely reporting from 58 counties. Though courts and law enforcement agencies are mandated to report within 30 days of final case dispositions and the CA DOJ’s policy is to update the data system within 90 days of receipt, a substantial portion of arrests did not contain dispositions. We assumed that these arrests without dispositions were not prosecuted for the primary analysis. However, if cases with no dispositions in fact include some felony convictions, and felony conviction missingness is associated with county, it could contribute to some of the geographic variation in convictions. The analysis of change in variation across time could be biased if felony conviction missingness differed within counties in the year pre- vs. post-Prop 47. There are several pieces of evidence that provide some reassurance. First, missing dispositions were more likely in the post period, which we would expect to occur if missing dispositions were indicative of no conviction, since the classification of drug possession offenses was reduced. Second, cases with missing dispositions were less severe in terms of concurrent offenses, which would correspond with lower likelihood of felony conviction. Third, the sensitivity analysis assuming that cases with missing dispositions had resulted in felony convictions did not alter findings.
The impact of the study design on the potential for bias should be considered. By comparing events just within the year before and after Prop 47, we attempted to limit the effect of time trends in felony convictions, though some reduction in felony convictions could be attributed to a pre-existing trend towards leniency for drug possession. That said, the large and immediate reduction in felony convictions across nearly all counties is unlikely to have occurred in the absence of the policy change. We extracted monthly SUD-related hospital visits in California from October 5, 2011 – September 4, 2015, as collected by the Office of Statewide Health Planning and Development. These months were generated such that the analytic period began after the start of California’s Public Safety Realignment , the post-Prop 47 period could begin on the first effective date of November 5, 2014, and no visits after September 30, 2015 were included. The ICD-9-CM coding system underwent major changes when it shifted to the ICD-10-CM system on October 1, 2015, and we anticipated a period of unreliable coding in the early months of this shift. The study therefore uses only the ICD-9-CM coding system. All visits with a SUD-related condition as the principal diagnosis among patients ages 15-64 were included. These comprised the following ICD-9-CM codes: amphetamines dependence , nondependent amphetamine abuse , cannabis dependence , nondependent cannabis abuse , cocaine dependence , nondependent cocaine abuse , poisoning by cocaine , adverse effects from cocaine , hallucinogen dependence , nondependent hallucinogen abuse , poisoning by hallucinogens/psychodysleptics , accidental poisoning by hallucinogens/psychodysleptics , adverse effects from hallucinogens , opioid dependence , combinations of opioids with any other , nondependent opioid abuse , poisoning by opium , poisoning by heroin , poisoning by methadone , poisoning by other opiates and related narcotics , heroin poisoning , adverse effects from heroin , sedatives/hypnotics/anxiolytic dependence , nondependent sedative/hypnotic/anxiolytic abuse , drug withdrawal , drug-induced psychotic disorder with delusions , drug-induced psychotic disorder with hallucinations , pathological drug intoxication , drug-induced delirium , drug-induced persistent dementia , drug-induced persistent amnestic disorder , drug-induced mood disorder , drug-induced sleep disorders , other drug-induced mental disorder , unspecified drug-induced mental disorder , other specified drug dependence , combinations excluding opioids , unspecified drug dependence , other mixed or unspecified drug abuse , or drug dependence complicating pregnancy/childbirth/puerperium . Though they made up just 14.7% of all SUD-related visits, we restricted the analysis to principal diagnoses, considered to be chiefly responsible for the hospital visit, to reduce the possibility of finding a spurious increase in visits attributable to the rise in insurance coverage through the Affordable Care Act in 2014.