Sullivan also pointed to possible "complicating factors, " such as malnutrition, poor housing or crowded conditions.

CNN: Among the swine flu mysteries: Why only deaths in Mexico?

Many complicating factors, say Clark and others, further taint survey results, including geographical, cultural and racial differences among patients.

FORBES: Why Rating Your Doctor Is Bad For Your Health

There might be some complicating factors here such as the commissions being more properly payable to the estate (which it might have been if this was actually a settlement for money owed to your mother).

FORBES: Ask the taxgirl: Looking a Gift Horse in the Mouth

But there are strong complicating factors.

ECONOMIST: By-election boulders