By lot
Definition 1 of 2
Pro Tip 1/3Chance Decision
Remember 'by lot' suggests no control over the selection—it's all chance. 
Team leaders were chosen by lot, so everyone had an equal opportunity.
Pro Tip 2/3Not Personal
'By lot' indicates the decision isn't based on personal qualities or preferences. 
Roommates at camp are assigned by lot rather than friendships.
Pro Tip 3/3Fair Process
Using 'by lot' can imply a fair process where everyone has an equal chance. 
Volunteers for the task were picked by lot to ensure fairness.