The New York City Police Department (NYPD) has a long and distinguished history in the nation's most populous city. It also, unfortunately, has a long and infamous history of wide-spread corruption among its officers and detectives. As with many police departments, law enforcement has often been stretched thin, forced to patrol vast, heavily condensed areas with limited personnel. Especially in New York, with its long history of violence and corruption, the task is even more difficult. Police riots occurred in the nineteenth century, and instances of systemic corruption have been somewhat regular occurrences throughout the department's history.
The student's question specifies 1993 as a benchmark beyond which changes or reforms may have been institutionalized in the NYPD related to instances of corruption. The year may have been chosen because of the notoriety of what became known as the "Dirty Thirty" case, in which officers at the city's 30th Precinct were implicated in large-scale corruption, a case which followed the previous year's arrest of individuals, including NYPD officers, of "the Long Island Cocaine Ring." In response to the "Dirty Thirty" case, NYPD Commissioner Ray Kelly reformed the department's Internal Affairs Bureau, traditionally a much-loathed and occasionally inefficient branch responsible for ferreting out corruption within the department. Kelly's reforms gave added authority to the bureau and assigned a former federal prosecutor as its head.
With this as background, the question of how the post-1993 New York Police Department can better deal with corruption can be addressed. Unfortunately, the answer is a little grim. As noted, the NYPD has been riven with major corruption scandals throughout its history, and Commissioner Kelly's reforms did not end that problem. On the contrary, investigations into police corruption continue to reveal instances of police officers violating their oaths and breaking laws for personal enrichment. The 2015 revelation of wide-spread cheating on the exams police sergeants must pass for promotion to the rank of lieutenant, as well as the 2016 indictment of officers for corruption, suggest that the problem has not, and probably never will, go away. That said, there are measures that could be adopted that could help minimize the problem of police corruption. No police officer wants Internal Affairs or federal agents looking over his or her shoulder every shift, and the personnel do not exist that would allow for such an arrangement anyway. Internal Affairs Bureaus, however, must be robust and properly resourced, and Commissioner Kelly's policy of conscripting officers into Internal Affairs rather than relying on volunteers did constitute a promising start. By minimizing the stigma that accompanies assignment to Internal Affairs, there is a chance that more officers will be deterred from taking those fateful steps down the path of criminal corruption.
Most law enforcement officers do not join police departments with the intention of taking bribes and subverting investigations into criminal activities. As many cases nationwide have demonstrated, however, that evolution does occur, and with disturbing frequency. Policing a city like New York is inherently stressful, and occasional faults in the criminal justice system, at least from the police officer's perspective (e.g., evidence thrown out on a technicality), combine to adversely influence an officer's commitment to the law. This does not excuse police corruption, but it does, partly, explain it. The NYPD could, however, adopt a practice from the federal government's intelligence community. Polygraph exams and background investigations of all officers at regular intervals would put a serious dent in instances of corruption. It is the rare police officer who can pass a lie detector test targeting corruption, and increased frequency of background investigations would uncover cases of officers living beyond their means—often positive indicators of officers engaged in illicit activities.
Added scrutiny on individual officers is the only measure likely to decrease instances of corruption. Such measures, however, are very expensive and manpower-intensive. They represent the best option for tackling a centuries-old problem.