The career criminal, or, more pointedly, those individuals who participate in criminal acts on a
regular basis for both a central and constant source of income has, generally, a specific set of
identifying factors which, while conclusive in laymen's terms, fail to meet the criteria necessary
for scientific inquiry. While definitions exist as to what a career criminal is, the research
methods employed in determining these definitions are a large point of contention for criminal
justice theorists, especially due to their potential and virtually imminent inclusion to modern
hypothesis on the subject. These research methods include longitudinal data collection and
compilation, cross-sectional data collection and compilation, and, as at least one group of
theorists argue, the most efficient method, informative interviewing.

The longitudinal research method employs a data collection technique which focuses on the
duration of a particular act--in this case, the so-called criminal career--based not upon
specific incidents, but the length of time measured between such acts (Blumstein, Cohen, and
Farrington, 1988). That is, an individual's propensity for criminal conduct in a so-called
career mode would be measured first by the original act as an origin, then with the succeeding
acts, until a final point became evident. Therefore, such a research method would logically
conclude that an individual who performed or participated in criminal conduct on two
occasions several years apart would be considered a career criminal. It is for this reason, that
criminal justice theorists differ as to the applicability and relevance of the longitudinal research
method (Blumstein, Cohen, and Farrington, 1988).

Since the longitudinal research method could construe two independent--or even two
interdependant--criminal acts as the foundational make-up of a career criminal, theorists may
hypothesize incorrectly as to the actuality of an individual having a career based in criminal
behavior. Because it is widely believed by opponents of the longitudinal research method that
the mere occurrence of two criminal acts spaced out over an individual's lifetime or testing
window is not indicative of the so-called career criminal modus operandi, the research
method has increasingly lost its popularity and application in such studies, unless, of course, it
is supported or otherwise confirmed by other utilized research procedures (Blumstein,
Cohen, and Farrington, 1988). One of these alternative testing and research methods is the
cross-sectional data collection and compilation model.

The cross-sectional data collection and compilation model, when applied to the criminal
career hypothezation, measures the probability of occurrence of a particular act of criminal
conduct or other so-called criminal behavior. The cross-sectional model allows for a glimpse
into each individual criminal act which may be thought to, when compiled, comprise a
framework which indicates that individual is a career criminal. For this reason, the
cross-sectional model is infinitely more applicable and accurate in determining, or at least
providing indicators which would lead to a determination, of conduct constituting that of a
career criminal. While such assistance is immeasurable for a determination of whether or not
an individual is a career criminal, it still falls short of a definite model for such identification.
For this reason, many criminal justice theorists feel that the individual application of the
cross-sectional model is inappropriate for its unsupported inclusion into relevant scientific
hypothesis. Once again, however, when such data is adequately supported or otherwise
confirmed by other information, inclusion is proper.

Criminal justice theorists have relied on either one, or both models since the inception of
investigation into all areas of criminal behavior. Such data, however, comes under fire if, and
when, other theories surface which either provide additional information, or information which
is more in-depth and in deference to that data already obtained and reported upon
(Gottfredson and Hirschi, 1988). The dilemma, of course, is that regardless of how detailed
and in-depth even the most comprehensive of testing techniques are, there is always one
method which is the most detailed, as it originates from the primary source. This data is called
informative interviewing (Gottfredson and Hirschi, 1988).

Informative interviewing is a method through which criminal justice theorists acquire
information from the primary source (Gottfredson and Hirschi, 1988). In the case of the
present issue, deliberating over the question of what behavior is indicative of a career
criminal, information would most probably be extracted from those individuals who exhibited
the stereotypical traits of