The D.C. Criminal justice system should focus on getting convictions rather than being satisfied with large numbers of arrests, according to a newly released study based on arrest and prosecution figures for the District of Columbia in 1974.

D.C. Police Chief Maurice J. Cullinane said the report by the Institute for Law and Social Research "dramatically illustrates that our criminal justice system is not really designed to get a maximum number of convictions." Its conclusions were "certainly not new to us," he added.

However, he questioned one aspect of the report that suggested police officers be rewarded monetarily and other wise for making large numbers of arrests that end in convictions. To institute such a process, Cullinane said, could result in "some type of bounty system" that would be undesirable.

Cullinane said he did not believe the report was critical of his agency, but merely analyzed certain aspects of the criminal justice system.

"The report convincingly points out the ineffectiveness of the criminal justice system as it currently functions; it identified some problem areas and some areas where progress has been made," Cullinane said.

In face, the report praised the cooperation between Cullinane and U.S. Attorney Earl J. Silbert and said that new joint programs such as the career criminal program for repeat offenders and the phony fencing operations, known as Sting, were in the forefront of criminal justice innovations.

Generally, the report produced statistical data to illustrate a theory that is well known to observers of the criminal justice system: Large numbers of arrests made by police never result in conviction, for many reasons, ranging from improper police tactics to arbitrary decisions by prosecutors to drop cases that they feel cannot be proven in court.

The report said that more than 70 per cent of the arrests made in Washington in 1974 for serious crimes did not result in convictions, an attrition rate that the report said appears to be a "common phenomenon nationwide."

"It is likely to be difficult for many persons to see how justice is done in a system in which the majority of offenders are not arrested, the majority of arrestees are not convicted and the majority of convicted defendants are not incarcerated," the report said.

The study was prepared for the Law Enforcement Assistance Administration by the Washington-based Institute for Law and Social Research.

The arrests that "wash out of court" when they are brought to the prosecutor are supported by less tangible evidence and testimony from witnesses than those that result in conviction, it said.

In robbery, larcency and burglary cases, the study indicated that the likelihood of conviction increased when less time elapsed between the offense and the arrest. The shorter the time span, the greater the police officers' ability to collect tangible evidence of the crime, the study found.

"One way to induce arresting officers to obtained better evidence is to expand their perspective of their own performance beyond the number of arrests they make," the report said.

"Arresting officers are likely to bring better evidence to court when their incentive to increase the number of convictions they produce, particularly in cases involving serious offenders, exceeds their incentive to increase the number of arrests they make," the report said.

The study found that more than half of all the arrests in D.C. in 1974 that led to conviction were made by 15 per cent of the 2,418 police officers who made arrests; or 8 per cent of the entire police force.

Of the arrests made by these 368 officers, 36 per cent resulted in convictions, compared to a 24 per cent conviction rate for the arrests made by the remaining 2,050 police officers who made arrests.

While the report noted that there were "substantial differences" among police officers in their ability to make arrests that lead to convictions, "what is less evident are the reasons why some officers appear to be so much more productive than others.

"While some of the officers who tend to produce more convictable arrests may do so as a result of their assignments, the highly productive officers can be found in every major Washington assignment," the report said.

"Moreover, even if some assignments may present greater opportunities for the officer to make arrests, this does not ensure that the officer will necessarily produce more arrests that lead to conviction."

The report suggested that police departments might want to recognize its officers who produce more arrests that lead to convictions with more rapid promotions, special recognition or bonus pay.

The report noted however, that if productive officers are promoted, they should, if possible, be allowed to remain in positions where "they can continue to produce arrests that lead to convictions."

Traditionally, the police have measured their performance with statistics that "may have little to do with crime control," the report said, such as numbers of arrests, numbers of reported offenses cleared by arrests and the ratio of arrests to offenses.

These figures are easily constructed and are not readily influenced by other agencies, the report said, and can also "induce police resources to be diverted away from the purpose of ensuring that arrests hold up in court through sound police investigation and witness handling procedures and through cooperation with the prosecutor."

The report concluded that "the police can make a greater contribution to the criminal justice system by expanding their perspective of their own role from that of making arrests to that of making good arrests."

At his press conference last week, Cullinane pointed out that a large amount of a police officer's work never results in arrests and so therefore it would be improper to regard officers only on the basis of the number of arrests they make.

Police respond yearly to more than 600,000 calls for assistance, Cullinane said, and most of those situations are not such that arrests are warranted.

Cullinane also said his office has established several new procedures - including new training programs and reviews of cases that are dropped by prosecutors.