"Strong culture." "Enthusiastic employee base." "Strong business outlook."

Those are a few of the reasons Delta is ranked among the very top U.S. companies in W2O Group's most recent Relevance Index, W2O analysts explained in an interview this week.

Delta climbed to No. 6, behind only Google, Microsoft and other tech heavyweights, in the closely watched relevance index. No. 6 represented a climb from No. 11 the previous year.

"You're standing out among your competitors," said Gary Grates, Principal of W2O Group, a consultancy that devised the Relevance Index. "Your employees send a very strong signal about your culture. They treat your passengers like people, and it's being noticed."

Grates and Alan Chumley, W2O's Managing Director - Communications Analytics, explained that the Relevance Index gauges companies' ability to engage with key stakeholders – employees, values-minded customers, Wall Street – in a social and digital world. It captures an organization's vitality and viability.

In the study, W2O examined Fortune 100 companies in five areas:

1. Web search visibility as a measure of consumer interest in the brand

2. Amplification of content as a measure of public engagement

3. Employee feedback and commentary on public sites

4. Financial community perspectives on business strength

5. Perceptions of the company's CEO

Chumley noted that on sites such as Glassdoor, Delta employees are enthusiastic about the company, talking most often about the culture and customers.

Delta CEO Ed Bastian said ​recently, "The secret sauce to building – and sustaining – Delta's trusted consumer brand has always been our people, driven by our values and rooted in our strong culture. … Kudos to all 80,000 Delta people worldwide whose outstanding work allows us to Keep Climbing in everything we do."

Read Forbes' coverage of the Relevance Index and download the index​.

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