in staff.lua:
    -- number of staff includes consultant
    local staff_count = room:getStaffCount() - 1
    -- update general skill
    self:trainSkill(room.staff_member, "skill", general_thres, room_factor, staff_count)

l343:
function Staff:trainSkill(consultant, trait, skill_thres, room_factor, staff_count)
  -- TODO: tweak/rework this algorithm
  -- TODO: possibly adjust based upon consultant's skill level?
  --       possibly based on attention to detail?
  local constant = 12.0
  local staff_factor = constant + (staff_count-1)*(constant/6.0)
  local delta = room_factor / (skill_thres * staff_factor)
  self:updateSkill(consultant, trait, delta)
end