Insights / Research BriefFeb 26, 2021

“Drive and Wave”: The Response to LAPD Police Reforms After Rampart

Based on BFI Working Paper No. 2021-25, “‘Drive and Wave:’ The Response to LAPD Police Reforms After Rampart,” by Canice Prendergast, W. Allen Wallis Distinguished Service Professor of Economics, Chicago Booth
Key Takeaways
  • Police reform measures are under consideration in many US cities following the May 2020 death of George Floyd and the subsequent civil unrest.
  • Evidence from police reform proposals in Los Angeles suggests that such reform could have unintended consequences. Arrest-to-crime rates fell by 40 percent after reforms were initiated.
  • Other data, including suggestive police surveys, provide evidence of “drive and wave" behavior by policy officers.
  • The LAPD reforms were focused on police behavior and suspects’ response. To craft effective policy changes, police reforms should incorporate victim oversight.
In the wake of George Floyd’s death at the hands of Minneapolis police in May 2020 and the civil unrest that followed, many cities around the US have turned their attention to police reform measures. Of course, police reform is nothing new, and often comes in response to incidents that spark community outrage.

However, how do we know whether reform measures will have their intended effect? Are there unintended consequences and can they outweigh intended benefits? Can police reform measures alter the behavior of police officers and crime suspects? These and other timely questions motivate “’Drive and Wave:’ The Response to LAPD Police Reforms After Rampart,” a new working paper from Canice Prendergast of UChicago’s Booth School. Prendergast’s work extends beyond Los Angeles and offers important insights to those working to transform policing in America today.

Figure 1
Notes: This figure shows arrests for narcotics and prostitution compared to other arrests by the LAPD. From 1998 to 2002, narcotics arrests fall by 45%, but recover completely by 2006. Prostitution arrests also fall by 40% from 1998 to 2002.

Incentives matter, for police and suspects

Prendergast’s story begins in Los Angeles in the early 1990s when the LAPD instigated an anti-gang squad known as CRASH (Community Resources Against Street Hoodlums). By 1997, activities at one particular police precinct, Rampart (from which this scandal takes its name), had spiraled out of control. Events included a bank robbery carried out by one officer, the self-defense killing of a CRASH agent by an undercover LAPD officer, and the theft of three kilos of cocaine from the evidence room by another officer. That last case was the tipping point, as the offending officer confessed and cooperated, offering evidence on other officers. The upshot was over 100 overturned convictions and $125 million in paid lawsuits against the LAPD.

Clearly, some reform was in order, and there are three key dates that mark the ensuing response: 1998, 2001, and 2002. In 1998, the LAPD implemented a policy where any complaint against an officer automatically triggered an internal investigation. Complaints against officers soared and were sustained at high rates, resulting in suspensions, resignations and terminations at historic levels. For example, complaints increased from 2,712 in 1997 to 6,965 in 1998, 6,830 in 1999, 9,244 in 2000 and 7,450 in 2001. Penalties also rose dramatically. Between 1992 and 1997, an average of 13 officers per year were removed from the force for malfeasance. In 1998, 55 officers were removed, with 44 in 1999. Sources report that in the two years after 1998, over 800 officers were disciplined, 113 terminated, and many left the force rather than be investigated.

The arrest-to-crime rate falls enormously after the first oversight change: by 40 percent from 1998 to 2002 for all crimes (those with victims, known as Part 1, and victimless, Part 2), and by 29 percent for Part 1 crimes. When oversight was reversed in late 2002, arrest rates immediately increased and the rate for all crimes returned to its 1998 level by 2006.

To make matters worse for officers, the complaints process was lengthy, meaning officers could not be promoted or transferred while a complaint case was open. The average investigation time was 8.8 months in 1999 and 6.3 months in 2000. By the end of 2000, 9,512 complaints were pending against officers, and 9,122 the following year.

Needless to say, these oversight changes were not well received by officers, who believed that gang members were coordinating complaints against effective officers to deny them promotions. Surveys reveal the uncertainty that officers faced when engaging suspects, with 80 percent reporting in 1999 that they feared punishment for an honest mistake, and 58 percent reporting that their careers had been harmed because of a complaint. Importantly, nearly nine out of ten said that a fear of discipline prevented them from proactively doing their jobs.

This brings us to 2001, when the scandal brought a response at the federal level, from the Department of Justice. The DOJ issued a consent decree that went into effect in June 2001 that required better documentation of police activities (for example, street stops), an early warning system for problem officers, and more formalized policies for the use of force. Notably, though, the consent decree did not change the complaints procedure, as it determined that the department was already in compliance with its objectives. However, it did mandate resolution of complaints within five months.

That five-month deadline proved difficult, at best, with only about half of investigations completed on time. So, in November 2002, oversight was changed such that commanding officers could dismiss complaints that they deemed frivolous. Prendergast shows that, beginning in 2003, sustained complaints fell dramatically, and disciplinary measures across the board became less likely, even when an investigation ruled against the officer. This change to the complaints process was not publicized.

These changes in the complaints process serve as the basis for Prendergast’s analysis. He crafted a model wherein the likelihood of an officer arresting a suspect depends on whether the officer engages the suspect and uses excessive force (meaning any actions beyond his legal mandate). The officer’s actions are potentially revealed through an investigation, the likelihood of which depends on a complaint from either the suspect or the crime’s victim. This could lead an engaged officer to eschew force and makes him less likely to engage. An officer, in other words, is always considering the trade-off between engagement and a likely complaint. Importantly, though, this trade-off is complicated when there is more accountability to victims, a key insight for police reformers.  

How does such a dynamic play out in the data? The arrest-to-crime rate fell enormously after the first oversight change: by 40 percent from 1998 to 2002 for all crimes (those with victims, known as Part 1, and victimless, Part 2), and by 29 percent for Part 1 crimes. When oversight was reversed in late 2002, arrest rates immediately increased and the rate for all crimes returned to its 1998 level by 2006. The Part 1 arrest rate reversed by half of the initial decline. Prendergast interprets these outcomes as evidence of “drive and wave” disengagement, and he cites contemporaneous officer reports that corroborate this description.

To test or check his “drive and wave” hypothesis, Prendergast first looks at differences across crimes to see if officers appropriately respond and investigate. For Part 1 crimes, which have victims (say, a burglary or assault), officers are more inclined to respond, especially as these cases are typically called into a station, leaving a record. By contrast, Part 2 crimes, (like narcotics and prostitution) often rely on the officer witnessing the crime. In line with 

Prendergast’s “drive and wave” insight, narcotics arrests fall 44 percent from 1998 to 2001, and then increase by that amount afterwards.

A comparison across law enforcement jurisdiction provides similar results. If one were contending, for example, that drops in Part 2 arrests reflect an actual decrease in crime rather than officer disengagement, the same crime reduction should occur across other jurisdictions. To address this, Prendergast compared LAPD outcomes to those of the Los Angeles Sheriff Department (LASD), which polices a range of unincorporated cities in Los Angeles. Unlike the huge swings for the LAPD, the total arrest-to-crime rate for the Sheriff’s Department is essentially unchanged throughout the study period.

Prendergast further investigated the geography of Los Angeles policing to make cross-jurisdiction comparisons and found that the arrests of other agencies show none of the variation in either the arrest-to-crime rate or total arrests exhibited by the LAPD.

These behavioral responses by officers are not limited to arrests. The Consent Decree required that the LAPD collect and publish certain data after 2001, which allowed Prendergast to show other responses to the 2002 change. For example, use-of-force per crime rose by 35 percent between 2001-2002 and 2003-2006, while street stops rose by 70 percent, both of which are consistent with the paper’s “drive and wave” thesis. 

By failing to investigate crimes in a way that led to arrests, police harmed the victims of those crimes. Prendergast argues that the oversight changes created an imbalance in which the voice of victims in police oversight was largely ignored.  This observation offers implications for the current debate on police reform. In particular, it shows that enhancing oversight by suspects without strengthening the voice of victims may backfire.

Finally, Prendergast investigated the effect of these changes on the incidence of crime, in particular, homicide. LAPD homicides rose 49 percent from 1998 to 2002, while they were unchanged for the LASD. Homicides then fell 30 percent for the LAPD in the three years after 2002, while they rose for the LASD. These data, along with analysis of certain LAPD/LASD areas, allows Prendergast to infer that there was, indeed, an impact on homicides from the changes in complaint procedure.


Police oversight is challenging, at best. Observing police behavior by superiors is difficult, and typical managerial responses to incentivize employee behavior, like pay-for-performance, do not translate well to police work. Instead, oversight often depends on interested parties—that is, parties that have some skin in the game—claiming that an officer misbehaved. Further, it is difficult to know the mechanism by which officers changed their behavior: Were individuals acting on their own or in coordination with other officers? Further complicating efforts at reform is the lack of consensus for how to trade off any costs of police actions vs. the benefit of solving or deterring crime. Many, for example, would disagree on where the line exists between justifiable and excessive force. 

CLOSING TAKEAWAY Police response reflected an imbalance between suspect and victim oversight. This observation offers implications for the current debate on police reform. In particular, it shows that reforms that enhance oversight by suspects without strengthening the voice of victims is likely to backfire.

This work reveals that behavior of police officers changes when complaint procedures change, and not necessarily for the better. In LA, the reform proposals brought on by the Rampart scandal, which utilized public complaints as a way to investigate officer behavior, resulted in police withdrawal. Yet Prendergast stresses that his work is not an argument against police reform; rather, it raises this issue as an obstacle to be addressed and yields two insights. First, the particular form of oversight matters profoundly, and can cause large responses in arrest rates. Second, and importantly, one reason for this is likely the absence of oversight by a key constituency—the victims of crimes.