factornoun
The amount of cruelty involved in the crime is one of the deciding factors in fixing a sentence.
Experts predict that the ability to cope with the heat may be a deciding factor in the outcome of the race.
The economy is regarded as the deciding factor in the outcome of the election.
One-upmanship was the decisive factor when it came to how high they went in the bidding.

SMART Vocabulary: related words and phrases

Decisions and deciding
ascription
be make or break for someone/somethingidiom
be on the horns of a dilemmaidiom
choose
clinch
conclusion
fish or cut baitidiom
flip
flip a coinidiom
get it togetheridiom
get something into your headidiom
judge
resolution
sleep
split decision
swing
swing the balanceidiom
take it into your head to do somethingidiom
take the plungeidiom
tightrope