Here's how we ranked the most powerful companies in America

We recently released our list of the 50 most powerful companies in America. Here's how we made that ranking.

We first compiled a list of companies to evaluate by looking at the top companies on the Fortune 500 list and Business Insider's list of the 50 best companies to work for in America.

We then used four main measures of a company's size and influence:

• Revenue: Looking at fiscal year 2014 financial reports, we gathered info on each company's top line.
• Number of employees: The total number of people employed by the companies also came from their 2014 annual reports.
• Google News mentions: On September 2, we measured the number of times companies were mentioned on Google News for the year between September 1, 2014, and September 1, 2015.
• Klout score: For most of the companies, we received their rankings from Klout, which measures the social-media influence of individuals and brands across all platforms.

Because revenue, number of employees, and Google News mentions spanned an enormous range including several orders of magnitude, we took the logarithm of each of these measures. Very roughly speaking, this rescales values based on how many digits they have.

To make each of our four measures comparable to each other, we then took normalized z-scores for each of the values. This puts each of the four measures onto a common scale with an average value of 0 and a "standard deviation" - or measure of how spread out the data are - of 1. This common scale allows us to more easily compare and combine measures.

To get our final composite power ranking score, we then simply added up the z-scores for each company, giving full weight to revenue, employees, and news mentions, and half weight to Klout score.