Don't know about Bloomberg. Just an outside view over the years. Zacks always seems to estimate high...I get really frustrated with them. They can do what they like, but I've always felt they were unfair with their estimates. The reasons...My thoughts. Zacks would not take into account things like the cyclical situation of a company. If the company hits it out of the park, they post higher the next quarter. They don't take into account the deferred maintenance of the company. If the company is absorbing another company, Zacks will still expect an easy transition. Every time I see a Zacks estimate, my mind runs to the phrase "give me a brake"!! It can also be a buying opportunity for the company. They miss slightly (or even a lot), if it's a solid company, step in with some toes... I don't like who Zacks will use for their consensus...Anyone it seems. Again, in a nutshell...Zacks will estimate high (without doing much research). They just put out the numbers to get eyeballs on them...
Seems like a "consensus" estimate would wipe out any edge from either. It would think you'd be better off looking at the individual estimators to see who has the best track record.
But Zacks simply compiles a consensus by asking analysts. So the source of a potential difference compared to Bloomberg or other vendors must be due to which analysts they include in the survey. Not because Zacks intentionally comes up with a high estimate.
Bloomberg provides estimates from ALL analysts individually + consensus I believe. Though not sure analyst/consensus estimates really mean anything.
Bloomberg compiles analyst estimates, similar to I/B/E/S. Both are quite good. I have not looked at Zacks. I think Yahoo data is pulled from I/B/E/S.