Interviewing at any company isn’t easy, but at some companies, the interview process is even tougher. To make things even more difficult, the average length of the entire interview process is increasing, from an average of 12 days in 2010 to an average of 23 days thus far in 2013, according to job candidate feedback shared on Glassdoor.

Glassdoor’s third annual report of the Top 25 Most Difficult Companies to Interview (2013)* uncovers which companies have the toughest interview process, according to job candidates over the past year, along with average interview duration, average interview experience (positive vs. negative), and overall employee satisfaction ratings to shed light into the question: Does a tough interview correlate to higher employee satisfaction?

This year, consulting firm McKinsey & Company takes the top spot for the third year in a row with its 3.9 interview difficulty rating. (Interview difficulty ratings based on a 5-point scale: 1.0=very easy, 3.0=average, 5.0=very difficult.) For perspective, the average interview difficulty rating on Glassdoor is 2.8. Check out the complete results:

See McKinsey & Company Interviews & Jobs

See ThoughtWorks Interviews & Jobs

See Boston Consulting Group Interviews & Jobs

See Gartner Interviews & Jobs

See Bain & Company Interviews & Jobs

See Rolls-Royce Interviews & Jobs

See ZS Associates Interviews & Jobs

See Google Interviews & Jobs

See Stryker Interviews & Jobs

See Hubspot Interviews & Jobs

See Paycom Interviews & Jobs

See Vistaprint Interviews & Jobs

See Teach for America Interviews & Jobs

See Procter & Gamble Interviews & Jobs

See Avaya Interviews & Jobs

See Microsoft Interviews & Jobs

See BlackRock Interviews & Jobs

See Sapient Interviews & Jobs

See Citrix Systems Interviews & Jobs

See NVIDIA Interviews & Jobs

See Informatica Interviews & Jobs

See Facebook Interviews & Jobs

See Guidewire Interviews & Jobs

See Caterpillar Interviews & Jobs

See Rackspace Interviews & Jobs

Did you recently interview? What was your experience like? Share an interview review.

*Report based on companies with at least 20 interview difficulty ratings and 20 company ratings between 7/24/12-7/23/13. Note, companies also received at least approximately 20 interview experience ratings and interview duration reports, respectively. For the purposes of this report, reviews from interns, summer part-time employees and student candidates are excluded. Interview and company ratings based on a 5-point scale. Interview difficulty ratings: 1.0=very easy, 3.0=average, 5.0=very difficult. Company ratings: 1.0=very dissatisfied, 3.0=OK, 5.0=very satisfied.