The college graduate population increased over time, but to get a better idea of the trends within this overall growth, a cluster analysis was used. Three distinct trends emerged. When more than three clusters were produced, the extra groups contained too few cases to be considered for analysis, and thus were eliminated. All three clusters started out with low proportions of college graduates, around 5-15% in 1960. Over time, these clusters diverged, with the largest growth reaching nearly 60% by 2000 (shown in yellow), while the lowest (turquoise) remained below 10% and the middle cluster (purple) peaked at about 30% in 2000. The greatest increases occurred in tracts bordering Cambridge, home to MIT and Harvard, and near Boston University, which is logical. The large number of graduate students attending these schools boosts the number of people with Bachelor’s degrees. The tracts with moderate increase primarily surround the tracts with the highest increase. The majority of tracts mirror the overall trend (see page one) of modest but steady growth. This cluster analysis identifies two underlying trends of higher increases that are masked by the overall trend.