The Interview Process takes time:
Stage 1: Resumé:
In this stage, you'll submit your resume online. They'll screen the resume, and get back to you.
Stage 2: Testing:
If you pass stage one, they'll invite you for analytical testing. You'll sit in a room, and receive an introduction about the company (don't wait until then to do your research!). You'll then have 1.5 hours to take a test; the test is a very standard case-studies test, where you'll be given case studies and asked questions about the studies.
Stage 3: HR Interview:
If you pass stage 2, you'll be invited to an HR interview. The interview is simply a standard personality filtering. They want to see who you are, why you want to join the company, etc. There's no reason to be worried about this stage - just present yourself and who you are.
Stage 4: Case Study / Manager/Principal's Interview: If you pass stage 3, you'll be invited for a Case Study / Manager/Principal's Interview. In this interview, you'll be given a case study to crack, and then asked to present your findings to a manager or principal at the company. The case study is challenging - it is best to practice case studies online (McKinsey, Deloitte, BCG, Oliver Wyman) to prepare yourself for this case study. I won't share what the case study was, but it was challenging.
Stage 5: Partners Interview
If you pass stage 4, you'll arrive at the Partners Interview. In this interview, you'll meet with partners for interviews. Things to know about TASC: TASC is a very serious company and is a leader in their field - it's not a company that you'll get accepted to just because you've applied. I found HR to be incredibly nice and helpful throughout the process. Other reviews say noise is a problem at the office when taking tests or preparing for case studies, I didn't find that to be the case.