Agenda - Council - 06/28/2016 - Laserfiche WebLink

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154 That is, we subtract the average for all sewered communities from each community's measure and divide by the standard deviation.' The specific formulas for determining the Z-scores for each community are: * —� = �,4/�vT/�bA�� --Share - 0�GG\ � 025 *ouxms `---'—'` �� --' p Z JoblWorker Balance =(Community's J0b/N/oOherBalance Ratio - 1.09A � 0.52 These Z-scores can be positive (if the community has a h ig her-th an -average ratio or proportion) or negative (if the community has a lower-th an -average ratio or proportion). Values of Z scores represent how many standard deviations each community is from the average ratio or proportion, which is represented by aZscore of0. For example, a community with aZscore of+2.0 has asubstantially higher ratio or proportion than average, and 8c0rnrnunity with 8Zscore 0f-2.0 has 8substantially lower ratio or proportion than average. Next, weresmded both sets of Zocores to percentages so that the pre -adjusted allocation would not be increased by more than 100% or decreased by more than 100Y6.mThis simply changes the scale of the standardized scores; it does not change their distributions. The result is aoet ofadjustment factors that can be weighted as desired to achieve the intent of the policy. For example, weighting each adjustment factor at 50% would a||ovv existing affordable housing and job/worker balance to affect the adjustment step equally. We weight the affordable housing adjustment at 67% and the j0b/vv0rkerb8|8nce adjustment at 33%, allowing affordable housing to have twice as much influence on the allocation as job/worker balance. We do this because the existing housing stock is a more stable and place -based indicator; workers are more likely to move than housing units are. Table B-2 shows these calculations for Chanhassen and Maplewood. For example, 34% of Chanhassen's existing housing units are affordable to low-income households— lower than 66%, the average share for all sewered communities. This is reflected in the Z score of +1.28 for Chanhassen's housing measure. (The actual Z score is -1.28, but we reverse the sign because the original measure does not go in the desired direction: communities with lower -than -average existing affordable housing shares have their allocations adjusted upvv8rdo]W18p|evv00d'oaffordable housing share 0f83Y6,though, iohigher than the average of00Y6;itreceives aZscore of-0.08. If we multiplied the pre -adjusted allocation by the standardized scores in Column C to calculate the adjustments, some communities' allocations could be negative or more than their forecasted growth. The rescaled standardized scores described above avoid this problem: Chanhaaoen'oreoca|ed housing score io+0.38, while W1ap|evvood\u io0.20. Applying weights (Column El to the reocaed Z scores (Column [) yields the final adjustment factors (Column F): +26% for Chanhassen and -14% for Maplewood. The jobs adjustment factors work identically, although the sign of the Z score is not Appendices