If you’ve passed the technical assessment, it usually means that the organization is confident in your technical skills and now wants to make sure that you are a good fit. Typically, your interviewer is looking for a few different things:
Are you actually interested in progressive politics? What issues / candidates animate you?
Are you a nice person?
Are you a good communicator?
Will you fit into our team?
Do you have the technical chops to do this job?, e.g.,
What is your favorite function in [insert language/program here]?
How would you decide what mix of money to spend in digital vs. TV advertising?
How would you automate the process to do [some data processing task]?
Take a look at the Soft Skills section and be prepared to offer examples of those qualities.
Here are some things additional you should always be prepared to talk about:
A past technical project: what was the problem or question you were trying to answer, what data did you use, what tools and methodologies did you apply, and what were your results?
Your technical assessment: this may or may not come up, but you should have a copy up in front of you. Your interviewers may want to ask you clarifying questions, and they’ll almost certainly ask how you would extend your work with more time.
An interview is also your opportunity to ask questions, but make sure you ask good questions. Bad questions demonstrate a lack of awareness about the job or the organization. Good questions make the interviewer think that you're a curious, thoughtful person.
Here’s something you should always ask about:
What are the next steps in the process?
When should I hear back about whether or not I’m moving on?
After your interview, send a thank-you note (by email). Ideally, your note should reference the interview you just had.