Resume: Is little time on a job a red flag?

Hey guys,

I have a question to ask you. When adcoms are looking at your resume and see that you stayed on a position for a short period of time (let´s say less than 9 months), is that a red flag? I guess that it will depend on some factors such as:
- whether you have a record of short periods in all of your positions (that may mean that you don´t have commitment or that you don´t really know what you want).
- what that change meant (a promotion, a change of career, a change of industry)

But all in all, what is the common perception about this?
If I leave a job in which I stayed for little time when the application dates are approaching, is that necessarily a bad move? Or the answer is a big "it depends"?

Thanks!