Institute for Research on Equity and Community Health (iREACH), Christiana Care Health System, 4000 Nexus Drive, Newark, DE 19803, United States.
Institute for Research on Equity and Community Health (iREACH), Christiana Care Health System, 4000 Nexus Drive, Newark, DE 19803, United States; Helen F. Graham Cancer Center & Research Institute, Christiana Care Health System, Newark, DE, United States.
Spat Spatiotemporal Epidemiol. 2022 Jun;41:100482. doi: 10.1016/j.sste.2022.100482. Epub 2022 Jan 21.
Aggregating point-level events to area-level units can produce misleading interpretations when displayed via choropleth maps. We developed the aggregated intensity method to share point-level location information across unit boundaries prior to aggregation. This method was applied to tobacco retailers among census tracts in New Castle County, DE.
Aggregated intensity uses kernel density estimation to generate spatially continuous expected counts of events per unit area, then aggregates these results to area-level units. We calculated a relative difference measure to compare aggregated intensity to observed counts.
Aggregated intensity produces estimates of event exposure unconstrained by boundaries. The relative difference between aggregated intensity and counts is greater for units with many events proximal to their borders. The appropriateness of aggregated intensity depends on events' spatial influence and proximity to unit boundaries, as well as computational inputs.
Aggregated intensity may facilitate more spatially realistic estimates of exposure to point-level events.
当通过面域图展示时，将点级事件聚合到面域单元中可能会产生误导性的解释。我们开发了聚合强度方法，以便在聚合之前在单元边界上共享点级位置信息。该方法应用于特拉华州纽卡斯尔县的普查区中的烟草零售商。
聚合强度使用核密度估计来生成每个单位面积的事件的空间连续预期计数，然后将这些结果聚合到面域单元。我们计算了相对差异度量来比较聚合强度和观测计数。
聚合强度产生不受边界限制的事件暴露估计值。对于边界附近有许多事件的单元，聚合强度与计数之间的差异更大。聚合强度的适当性取决于事件的空间影响以及与单元边界的接近程度，以及计算输入。
聚合强度可能有助于更真实地估计点级事件的暴露程度。
