(April 22, 2012; rev. Dec. 28, 2012))
The main Discipline Disparities page of this site discusses interpretations of data on racial differences in school discipline rates in light of the pattern whereby the rarer an outcome the greater tends to be the relative difference in experiencing it and the smaller tends to be the relative differences in avoiding it. This sub-page discusses attention given to the fact that relative differences in discipline rates are larger in Philadelphia suburbs than in Philadelphia itself without recognition that relative differences in discipline rates will tend to be larger in suburbs (where discipline rates are generally low) than in cities (where discipline rates are higher), though relative differences in rates of avoiding discipline will tend to smaller in suburbs than in cities.
Much of the attention this site gives to the pattern whereby the rarer an outcome the greater tends to be the relative difference in experiencing it and the smaller tends to be the relative differences in avoiding it involves the interpretation of patterns of relative differences during periods when overall outcome rates are changing. In that context patterns whereby, for example, as adverse outcomes decline in overall prevalence relative differences in experiencing them tend to increase while relative differences in avoiding them tend to decrease are almost universally misunderstood. The statistical pattern is equally misunderstand when it comes to comparing the size of differences in different settings. Thus, all sorts of theories are advanced to explain large relative differences in adverse outcomes in relatively advantaged populations without consideration that relative differences in adverse outcomes will generally to be large in such populations because adverse outcomes tend to be rare in such populations and without consideration of the fact that relative differences in favorable outcomes tend to be small in such populations.
See Sections B.4 to B.6 of the Scanlan’s Rule page and Sections E.1 and E.2 and the Whitehall Studies sub-page of the Measuring Health Disparities page regarding perceptions about large relative (racial) differences in infant mortality where parents are college-education, large relative (occupational) differences in morbidity and mortality among British Civil Servants, and large relative (socioeconomic) differences in Nordic countries. See the Disparities – High Income of the Lending Disparities page regarding perceptions concerning large relative (racial) differences in rejection rates among mortgage applicants with high incomes. See also pages 20, 40-41 of Harvard University Measurement Letter.
An April 15, 2012 Philadelphia Inquirer article styled “A Punishing Racial Disparity in Suburban School Schools” pointed out that black public school students in Philadelphia’s Pennsylvania suburbs were twelve times as likely as white students to be suspended more than one whereas in the city of Philadelphia black students were only 2.8 times as likely as white students to be suspended more than once. The article reported opinions of an ACLU researcher as to what might be reason for the larger relative differences in the suburbs than in the city.
Like virtually all persons reporting on demographic differences in the law and the social and medical sciences, neither the article’s author nor the researcher considered that relative differences in discipline rates would tend to be larger in the suburbs than in the city because discipline rates tend generally to be lower in the suburbs.
I do not have a view on whether the fact of larger relative differences in multiple suspension rates in the suburbs of Philadelphia than the city itself is entirely a function of the lower rates of multiple suspensions in the suburbs. Nor do I have a view on whether, properly measured, differences between the circumstances of black and white students with respect to experiencing/or avoiding multiple suspensions are larger in one locale than the other. But it is impossible to address such issues without recognizing the way standard measures of differences between outcome rates tend to be affected by the overall prevalence of an outcome.
See also Gregory et al., in “The Achievement Gap and the Discipline Gap: Two Sides of the Same Coin?,” where the authors make the following point of the fact that racial disparities in discipline rates tend to be larger in suburban than urban schools, and draw inferences based on such pattern.
In fact, some research has found an inverse relationship between student demographics and rates of disproportionality in school discipline. Rausch and Skiba (2004), examining suspension and expulsion records across one Midwestern state, reported that Black students are at greater risk of suspension when compared with White students, not in urban schools but, rather, in more resource-rich suburban schools. Other research suggests that the context of school or district racial climate may have an influence on rates of disproportionality. Thornton and Trent (1988) reported that racial disproportionality in school suspension was greatest in schools that had been recently desegregated, especially if those schools had a higher SES student population. Conversely, Eitle and Eitle (2004) found decreased rates of disproportionality in school suspension in schools that became resegregated. Such data suggest that, at the school and district levels, financial resources, staff perceptions, and racial climate may be as important as student demographics in predicting racial disparity.
As discussed above, useful interpretation as to what such data suggest must be informed by an appreciation that relative differences in an outcome will tend to be larger where the outcome is less common than where is it more common.