An accountability partner is like a partnership where you mutually agree to coach each other and provide feedback on a regular basis. ... If you have an accountability partner, you usually get more personalized help with your goals because the other person is focused on your success.

How to Increase Your Chances of Success: Get an Accountability Partner
By Gustavo Razzetti

If you simply have an idea or goal, you are against all the odds. Consciously deciding to achieve something increases your chances from 10% to 25%. Once you decide when and have a clear how, your chances of succeeding become 50%.
Social commitment dramatically increases your odds.
When you commit to someone that you will do it, stretches your probability to 65%. Moreover, when you create a specific accountability appointment with a person you are committed to, the odds are in your favor: 95%.