Making sense of lead source for attribution

Question

I am trying to make sense of the relationships between the lead source fields in the lead/contact, account and opportunity objects.

Basically, my objective is to be able to analyse opportunities by lead source.

Except lead source is blank in the vast majority of cases.

2 questions:

1. Is there a scenario under which opportunity lead source gets populated automatically?
2. Is there a method I can use to populate lead source for existing opportunities based on contact data that is somehow associated?

Answer 1

Here are answers to your questions:

1. Is there a scenario under which opportunity lead source gets populated automatically?
   • Yes, when a lead has a Lead source and is converted to Account, Contact and Opportunity using Lead Conversion.
   • It is optional while creating new opportunity.
2. Is there a method I can use to populate lead source for existing opportunities based on contact data that is somehow associated?
   • Easiest option is to do it through dataloader, otherwise would need some customization like batch apex.

Additional detail, On Account object it's not by default. Refer this documentationfor more details.