Extracting information on leading objects

Is it true that in CMSSW, edm stores objects in decreasing pT order?

In addition to that, for analysis is PAT:Electron preferred over GsfElectron?

Hi, sorry for the delay in answering. EDM as a format does not impose any particular ordering for all collections. Some collections may be ordered by pT, some may not, depending on the exact circumstances of how they were produced. It is always safest to check.

Kati for the CMS open data team

For electrons, you can find the instruction for Run-1 data in Electrons and Photons – Basic Physics Objects