The multiplier method: scaling off your damages
The multiplier method is the industry's default approach. It takes your economic damages — medical bills and lost wages — and multiplies that total by a factor generally between 1.5 and 5, chosen based on injury severity, recovery time, and whether any permanent impairment is involved.
The per diem method: valuing each day
The per diem (Latin for "per day") method works differently. It assigns a specific dollar value to a single day of pain and suffering and multiplies that rate by the total number of days of documented recovery, tying the value directly to time rather than to the size of your medical bills.
Why 50% fault matters more than the method in Michigan
Whichever method produces your noneconomic estimate, Michigan's rule under MCL 600.2959 treats that whole figure as an all-or-nothing question tied to your own fault: cross 50%, and the entire noneconomic number — however carefully it was calculated — disappears. Meanwhile, the economic damages from the exact same case keep getting paid, just reduced by your fault percentage. So the real fork in the road for a Michigan claim isn't multiplier-vs-per-diem; it's whether the fault allocation lands at 50% or 51%.
A separate threshold for car accidents, before either method even applies
For a car accident claim specifically, neither valuation method matters until a more basic question is settled: does the injury clear Michigan's no-fault "serious impairment of body function" threshold at all? If it doesn't, there's no noneconomic damages claim to value with either method in the first place — only the underlying no-fault PIP benefits apply.
Neither is required by Michigan law
Both methods remain negotiating tools, not a formula Michigan courts are required to apply. A jury retains discretion to award whatever amount it finds appropriate for noneconomic damages — subject to whichever cap and fault rule genuinely apply to the case.