What is the headline?
The headline is where you give a direct, basic answer to the question. Whatever they ask, address it head on. If you don't address the question head-on, you seem evasive.
For example: What is your biggest strength?
Headline might be: My biggest strength is that I excel in fast changing situations. I know how to effectively set priorities and quickly solve any problems that crop up.
With a good headline, the interviewer will see that you are a fit for the job.
What is the proof?
The proof then shows me that there is something real behind what you said in the headline. This can be a story based example or a couple of highlighted accomplishments.
Over the past 5 years, I've taken on 17 6-month projects. And with my team, I delivered every one on time, despite the usual technical problems.
(You can share a longer proof point or multiple proof points, but I would suggest keeping it to less than one minute of speech - about 120 words, and to vary the length so not all are very long or very short).
With a good proof point, interviewers will believe you actually have the talent you mentioned in the headline. With a great proof point, you will have a memorable story or example that shows why you are better than any other candidate.
What about the connection?
You want to wrap up your answer by pointing out how what you shared in the headline is of value to the interviewer and the interviewer's company. This can be a statement or a question.
Example of a connection statement:
Based on what I've learned so far, it seems like this company is taking on a lot of new client projects, and I am excited to jump in, overcome the technical challenges, and make sure our work is delivered on time.
Example of a connection question:
It seems like this company is taking on a lot of new client projects, which is exciting. How are you managing their timelines?
You may think interviewers know how the talent you mentioned in the headline helps their company and team. They probably do, but during the interview, their head is swimming. So it's valuable to remind them. Plus when you draw these connections, you show that you are thoughtful and did your homework before the interview.
Those are the three parts of the perfect interview answer. And if you look at the answers to each of the three questions above: What is a headline? What is the proof? What about the connection?, each one was answered in this exact 3 part format.