CM from the US-Non-Immigrants blogspot has posted some good explanation on simple cases for adjudication. Thought of sharing it below, in case u haven't read it yet:
http://us-non-immigrants.blogspot.co...ctions-eb.html
Definition of simple case for an USCIS adjudicator is
a) It is completed in all respect. He does not have to go looking for the information in the system before he makes a decision to ask for initial or additional evidence. They are required to do due diligence before they issue any RFE.
b) Case where Alien Number file is already generated and available to pull. This file tells all the record when an applicant last entered in US. Records about status maintenance since first entry to US. it has all information about you. If a file is not present it is generated. For most cases it is created during I-140. If you will not write your A# in the I-485 applications, they have to go looking for your information.
c) Case where FP and BCIS check come complete early. Please note BCIS checks can take some time depending on your country and respective consulates.
d) Have clean Birth and Marraige Certificates. Adjudicators depending upon experience would know about secondary evidence, others will have to send files to supervisor for review. Please note supervisor is a group leader of 5-10 adjudicators. More cases that will go to him more it will take time for him to approve your case.
d) Cases were employee currently resides in same state as PERM stated state makes things pretty easier. Any discrepancy requires seeing your EVL and current title. If you are not on site then where are you? Anyone working at client site could require additional review. Simple case will be you are currently working with sponsored employer at stated salary.
e) If your company is acquired, mergered or changed names, your company information is checked along
http://www.dnb.com/ site. If they cannot find your company name in the list. more review is required. It may require calling your employer to verify. If 180 days are past, you may receive RFE for new EVL.
f) Last but not the least, it all depends upon when and who picks up your case file.
These are just examples of complications which can increase processing times for a case. Anything that is straight forward will be approved by USCIS adjudicators wihout consulting with or sending it to supervisor for blessing. No one cares if it is a STEM or Business applicant. If you work for small or big company. As long as you and company are not blacklisted you are good.