Based on personal observations.
Interview Rounds
The more rounds the less serious/motivated is the company. Interview rounds include pre-screening calls with HR. The higher the number of rounds, the worst the culture is.**At the Interview.**Is the manager bombarding you with technical questions, like an inquisition? Are they asking technical questions that are in no way and manner specified in your resume? Is the attitude antagonistic as if trying to find excuses not to hire you? Trust your gut and the vibes and walk out unapologetically.
Response Time
If you apply for a job and only hear back with an interview invitation after a month, it is concerning. Well into the 21st century, such delays in communication indicate an antiquated and stuffy work environment where sending an email becomes a feat of quantum mechanics. Not a gigantic red flag…if you are desperate for a paycheck…but something to be mindful about.
The Job Offer
If the employer is serious in hiring, they will make that known immediately after the interview. It doesn't need to be a formal job offer. It can be expressed vocally, while walking you to the elevator. It can be a phone call while you are waiting for the bus or cab home. Bottom line is, they will not wait a week. They will not be interviewing more people. The most is 48 hours. If 48 hours have passed since the last interview, it is a rejection.
Anyone wants to chime in?