Fig. 2

Correlogram showing correlations of the 50 measures across the 29 medical schools. Positive correlations are shown in blue and negative in red (see colour scale on the right-hand side), with the size of squares proportional to the absolute size of the correlation. Significance levels are shown in two ways: two asterisks indicate correlations significant with a Tukey-adjusted correction, and one asterisk indicates correlations significant with p < 0.05. For abbreviated variable names, see text. Measures are classified in an approximate causal order with clusters separated by blue lines