Nielsen Analyst interview questions

I found the posting online and after applying, I was notified that Nielsen wanted to conduct a phone interview the following Monday. The phone interview was very short, really only 2-3 'interview-type' questions and then they asked my availability to take a skills test, which I scheduled for that Friday. The skills test had short word problems, and essay, and I had to write a letter to the President of a fictional company with my recommendation for a soap product. The test was very similar to tests I've taken in my MBA program; a fair amount of math and pretty challenging, but not too difficult. After the test, I had a short interview with the two Nielsen staff members - this client company had a total of 3 Nielsen Analysts on-site. This was somewhat unexpected and somewhat informal. However, it went well and I left to await email notification about my skills test. After a week or three, I received an email stating that I passed the skills test and that I was to schedule a half-day interview with four managers from the client company. I met for about an hour with each person where they asked some in-house behavioral, or STAR interview questions. I left very confident in my abilities and my interviews, but after more than a month, I received a generic rejection email. The position is still posted to this day. I am dissappointed in myself for not getting the job, but I it was a great interview process experience. The Nielsen Analyst is physically placed within large companies to process and report on the client's data. Given that relationship, I left the interview with a feeling that there is a level of frustration between this client company and Nielsen, which I can only assume that some frustration is somewhat common in other organizations in which a Nielsen Analyst is placed.