How we're calculating death in our HeartSaver experimental news game.

calculateDeath.js

var calculateDeath = function(hospital, pickupTime, travelTime) {
  var survivalChance = 1;

  // A victim’s chance of survival decreases by 7 to 10 percent / minute 
  // that passes without defibrillation.
  // http://www.heart.org/idc/groups/heart-public/@wcm/@ecc/documents/downloadable/ucm_438703.pdf
  survivalChance -= (0.10 * pickupTime);

  // Time in transit to ER (.58% / minute, via the Google Directions API)
  // http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2464671/table/tbl1/
  survivalChance -= (0.0058 * travelTime);

  // Medicare heart attack mortality
  // http://www.medicare.gov/HospitalCompare/Data/RCD/30-day-measures.aspx
  survivalChance *= (1 - (hospital.heart_attack_mortality_rate / 100));

  return (Math.random() < survivalChance);
};