It's a form of procrastination.

It happens when you convince yourself you can't go forward with a decision, because you haven't given it enough thought, done enough research or figured things out to get started.

It has the same root cause as all forms of procrastination. It is caused by the desire to avoid something unpleasant: you don’t want to get started, so you start searching for excuses to justify avoiding the unpleasantness.

And there really are fears, uncertainties or doubts, ...

You have to manage 2 realities: 

• Rationalization: Deal with your rationalization that you need more time to think, plan and research by preventing this excuse from working.
• Underlying fear: Even if you convince yourself that you are engaging in procrastination and...

Spending some time analyzing the possible options is good. But an indefinite amount of time is going to be bad.

The way to get past this is to set constraints. If you set these constraints in advance, then you can undermine the rational part of your mind from using them as a j...

• Set a decision deadline (for doing all the research and thinking) with a default (when the deadline passes, you’re stuck with the default).
• Start blindly, change later. Give yourself a default, and force yourself to work on it for a certain amount of time, before...

You need to remove the anxiety and fear of doing the thing you’re avoiding. Then, you need to remove or invert the pleasant feeling you get from stalling:

• Give yourself small doses of the thing you’re scared of to diminish the fear it generates.
• Punish yourself for fa...