“…The service needs assessment forecast was developed utilizing a grid database, where Finland is divided into 1 × 1 km size squares. For each 1 km2 square, the following background variables were defined: 1) risk category classification [ 15 , 16 ], 2) location in relation to Finnish road network (road connections, length of roads in the grid, and highest speed limit 80 km/h) [ 17 ], 3) municipality, hospital district, and university hospital area, 4) permanently resident population, 5) number of EMS missions (including other than HEMS) classified by dispatch urgency and code, 6) estimated response time of a ground-unit to the grid’s center, using historical response times of missions by the same urgency, applying the Inverse Distance Weighting (IDW) interpolation method [ 18 ], 7) Driving time and distance from nearest base to closest road point to the grid center, and from this point to University hospital or large-scale emergency hospital [ 19 ], and 8) flight time and distance from bases to the grid center, and from this point to the nearest university hospital or large-scale emergency hospital by average 220 km/h airspeed based on information received from FinnHEMS. The service need forecast was evaluated for each patient group.…”