The investigators hypothesize that spatial analysis of the location data of ambulance calls can improve prehospital care provided by Aman Foundation in Karachi, Pakistan by decreasing ambulance response times for high acuity patients. In Aim 1, the investigators will develop a conceptual framework for prehospital care in low- and middle-income countries (LMICs) to anchor this project in Aims 2 and 3. In Aim 2, the investigators will analyze the location of calls to identify geographic areas with delayed responses for patients with higher severity of illness. As part of their quality assurance/quality improvement practices, Aman Foundation routinely collects location data from GPS devices in their ambulances for each call. Based on the analyses in Aim 2, in Aim 3 the investigators will position ambulances where there are clusters of delayed ambulance calls for high acuity patients to improve response times. This period will be compared with a previous, control period and will be analyzed to identify possible new clusters.