A decision to detain an individual for investigatory purposes is mandated neither by statute nor by police procedure. As discussed, it is a discretionary tool used by police officers engaged in aggressive patrol practices designed to fulfill their crime-fighting function. As the majority of police-citizen encounters occur in the absence of any outside supervision, front-line police officers, therefore, have a great deal of discretional latitude throughout the decision making process. Given this background, all of the previously described uncertainties lead to only one certainty: when the rules themselves governing investigative detention are at best ambiguous, and at worst, yet to be determined, confining and structuring police discretion is virtually impossible.
Recognizing that the front lines of most police organizations are predominantly saturated with younger, less experienced officers, this virtually untrammeled discretionary authority serves to facilitate the potential of abuse. Moreover, for the officer who is already inclined to use his or her discretion inappropriately, a lack of clear and comprehensive rules substantially increases this risk.
While the police are expected to exercise discretion in detaining individuals for investigation, there is great concern about what factors influence these decisions. Most of the literature on police discretion is focused on the decision to arrest or search a suspect. It is important, however, to step back and examine what precedes these decisions. Prior to the actual encounter, a police officer typically forms a suspicion that a suspect is engaged in, or about to engage in, criminal behavior. Consequently, it is this earliest stage, when an officer formulates suspicion prior to stopping a citizen, which has the most profound consequences for participants in the criminal justice system. While the formation of suspicion is primarily driven by situational factors related to the nature of the suspected criminal behaviour, it can be based on more than the mere conduct of the person arousing suspicion. A combination of an officer’s personality, bias, and prejudice, developed through his experiences on the job, partly explains how the officer responds in interactions with citizens. Additionally, the ethos of the police model under which the officer operates can contribute to influencing the discretionary decision making process. Through personal experience, a direct proportional relationship exists between the crime-fighting emphasis promoted by police managers and the tendency for officers to engage in more proactive and aggressive patrol practices. Although this crime fighting self-image is more rhetoric than reality, its potential influence on the exercise of police discretion should not be discounted. If the police see themselves as combatants engaged in a competitive endeavour, they will no doubt be more inclined to ignore the formal limits on their power in order to achieve their perceived objective - catching criminals.
The question is not really about the appropriateness of discretion, as much as a concern with controlling its operation. After all, discretion can lead to injustice if it used in abusive, discriminatory, or capricious fashion. Ideally, the formation of suspicion which precedes a discretionary decision should be aroused by the actual behavior of suspects. Police suspicion should be objectively based on prior knowledge, observation, and the time and place of an incident. Preventive police action should not be allowed, however, when it is motivated by a suspicion of criminal activity solely, or primarily, based upon the personal attributes of the target. Regrettably, real-world experience suggests that both race and social status are important considerations for police officers in forming suspicions. This raises serious equal protection questions that are posed by the selective invocation and overzealous enforcement of law against the socially disadvantaged. While it is true that law enforcement may incidentally affect the ordering of social relations, nonetheless its primary purpose should not be the social control of marginalized groups.
In particular, the decision to detain an individual for investigation may present opportunities for discrimination on racial grounds. If racist practice can infect the exercise of police discretion in other contexts, there is no reason to think that investigative detentions are somehow immune from its noxious influence. At the very core of the controversy surrounding issues such as racial profiling is a police officer’s initial decision to suspect that someone is involved in illegal behavior. No doubt some police officers hold overtly racist views that may lead them to abuse their detention powers. Much more likely, however, is the risk that many more police officers subconsciously operate on the basis of stereotypical assumptions regarding visible minorities. An officer’s assessment of her or his grounds for detention may be partially skewed by a belief that certain visible minorities are more likely to commit crimes. Although race is not a legitimate justification for an officer to take formal action against an individual, there is sufficient evidence to conclude that the law is administered inconsistently in a way which both “creates an impression of discrimination and allows for the introduction of personal prejudices into police practices.”
"While decisions to arrest might not be knowingly influenced by racial factors, they may be influenced by other equally disturbing considerations such as socio-economic status.While a police officer may not be racially motivated, he may appear to be discriminating against the black, when in fact he may be mainly implementing departmental goals by deciding against the poor, the unemployed, and the residentially unstable, many of whom are black." 
Regardless of the actual source and character of discriminatory influences on an officer’s investigative detention discretion, decisions to detain which are based on prejudicial personal or institutionalized dynamics are those which should be condemned. In brief, granting overly broad discretionary authority to police officers without adequate boundaries unleashes the disconcerting potential of allowing discriminatory actions to be concealed as valid exercises of discretion.
It must also be recognized, however, that given their virtual monopoly over information surrounding investigatory stops, recognizing, exposing and condemning these potentially abusive practices is extremely difficult. Using Manning’s dramaturgical analogy, officers will not often find it very difficult to present a front-stage version of events that appears reasonable to a trier of fact while controlling the back-stage discriminatory reality.
 G. Alpert, “Police Suspicion and Discretionary Decision Making During Citizen Stops” (2005) Criminology 43.
 Stribopoulos 2005, supra.
 Stribopoulos 2003, supra.
 G. H. Williams, “Police Discretion: The Institutional Dilemma – Who is in Charge?” (1983) 68 Iowa L.
 Alpert, supra.
 Manning, supra.
 J. Stribopoulos, “Unchecked Power: The Constitutional Regulation of Arrest Reconsidered” (2003) 48 McGill L.J. 225
 M. Freeman, “Controlling Police Discretion” (1981) 6 Poly L. Rev. 51.
 Alpert, supra.
 M. G. Abernathy, “Police Discretion and Equal Protection” (1962) 14 S. C. L. Q.
 Young, supra.
 K. Davis, “Controlling Racial Discrimination in Policing: A Discussion Paper” (1993) 51 U. Toronto Fac. L. Rev.
 Alpert, supra.
 Stribopoulos 2003, supra.
 Williams, supra.
 Davis, supra.
 Manning, supra.