HOW TO ANALYSE DATA IN CASE INTERVIEW

One of the skills that's being tested during a case interview
is something I call data sufficiency. 

Basically, you have a bunch of data and the question is do
you have ENOUGH data to make a particular conclusion.

This is certainly something that is tested during a live,
in-person, face-to-face case interview.

It is also a skill that is often tested in a variety of formats
including written tests before the first case interview.

An example of this is the McKinsey Problem Solving Test
which is a written test that evaluates your data sufficiency
skills (among others).

In parts of the McKinsey Problem Solving Test (also known
as the McKinsey PST), you are  given a bunch of data and
some possible conclusions. Your job is to figure out which
conclusions are or are NOT supported by the facts presented.

Now this test is not intended to torture you (though I know
some people might argue with me on this one).

It turns out this is a very important skill once you're on the
job as a management consultant, especially as a first year
analyst or associate.
Data sufficiency is an important skill to master.  Other
firms also look for this skills -- though how they do it
varies from McKinsey.

Most firms will just test for this skill implicitly during
a case interview and test verbally throughout the case. 

Some firms, notably Monitor and in some countries BCG,
are testing for this skill in written tests similar to McKinsey's.

These are all variations of the same thing.

Given a set of data, will you determine the correct, logical, and
factually supported conclusion every time?

It's important because if you can NOT do this correctly 100%
of the time, then consulting firms can not put you in front of
client without extremely close supervision -- in other words,
they can't hire you.