Prospective crime mapping in operational context Final report

Table 2.2: Knox ratios for Mansfield (values in bold are statistically significantaccording to the residual scores (not shown), N=1,566)MONTHS1 2 3 4 5 6100 1.26 1.10 0.97 0.85 1.02 1.03200 1.08 0.99 0.93 1.04 0.92 1.01300 1.00 1.07 1.01 1.01 1.01 1.13400 1.03 0.96 1.07 1.04 1.01 1.06500 1.01 1.06 0.97 0.98 1.11 1.05600 1.03 1.02 0.98 1.08 0.98 1.03700 1.03 1.04 0.96 1.00 1.01 1.02800 1.04 1.01 0.97 0.98 1.00 1.00900 1.03 1.06 0.97 0.96 0.98 1.031000 1.06 1.01 0.96 1.02 0.99 1.02A number of other cells are statistically significant in each table, namely those for 1,000m andone-month and 500m and five months. Due to the results for a large number of cells beinganalysed, some cells (60*0.05=3) will have significant values by chance. For this reason theywill be discussed no further. In contrast, the analyses for the cells in the top left of the tablesare based on an a priori hypothesis and are of clear relevance.Visual inspection of the Knox ratios in Table 2.3, shows that around 25 per cent moreburglaries occur within 100m and one month of burgled homes than would be expected onthe basis of chance, eight per cent more between 101-200m. 12 per cent more up to 100mand between 30-60 days. Otherwise, the number of burglaries approximate what would beexpected on the basis of chance. (Note that the Knox residuals cannot be interpreted aspercentage deviations from chance as they are actually z-scores, see preceding section).Table 2.3: Monte-Carlo results for Mansfield (values in bold are statistically significant,N=1566)MONTHS1 2 3 4 5 6100 1.26 1.12 0.92 0.90 0.99 1.08200 1.08 0.99 0.93 1.02 0.95 0.99300 1.00 1.06 1.00 1.01 1.00 1.17400 1.03 0.98 1.08 1.03 1.00 1.03500 1.01 1.05 0.96 1.00 1.10 1.06600 1.03 1.02 0.97 1.09 0.97 1.03700 1.03 1.04 0.94 1.02 1.00 1.01800 1.04 1.01 0.99 0.96 1.01 0.98900 1.03 1.05 0.96 0.98 0.98 1.001000 1.06 1.00 0.97 1.01 1.00 1.03To increase the sensitivity of the results, an additional Knox analysis was conducted toexamine the temporal pattern in more detail. Thus, weekly rather than monthly patterns wereanalysed. As noted above, these were computed using the Knox approximation rather thanMonte-Carlo simulation.7