Economist and Nobel laureate Robert Shiller struck a surprisingly bullish tone in a recent interview with Fortune this week, noting that several sectors of the market are actually relatively cheap, including tech stocks.

Using the cyclically adjusted price-to-earnings (or CAPE) ratio, a metric that he created, Shiller said he "would be inclined to recommend" what he sees as "undervalued" stocks.

"And that would be consumer staples, industrials, healthcare — and even technology," he told Fortune. 

Shiller developed the cyclically adjusted price-earnings (CAPE) ratio market valuation measure, which is calculated using price divided by the index's average historical 10-year earnings, adjusted for inflation,

"Right now, for the S&P 500, that ratio stands at more than 29, its highest valuation since 2002 and well above its historical norms. When it comes to tech stocks, though, the opposite is true," Fortune explained.

"We make an adjustment for the fact that technology stocks have always been highly priced, so recently they’ve been less highly priced overall than on average," Shiller said.

He did admit that some Silicon Valley companies and certain tech stocks do have excessively lofty valuations; Amazon stock, for example, trades at a PE ratio of 186 times earnings, while Facebook has a PE ratio of 40.

"I think you want to avoid some of them," Shiller said. He declined to specify which ones, Fortune reported.

Meanwhile, Newsmax Finance Insider Lance Roberts recently took Shiller's CAPE to task.

Shiller’s measure, created with Harvard University economist John Campbell in the 1990s, is called the “cyclically adjusted price-earnings,” or CAPE ratio. The index, sometimes called the “Shiller P/E,” essentially divides share prices by the average of 10 years' earnings adjusted for inflation. It compensates for extreme volatility by valuing share prices based on 10 years of earnings, rather than one year.

But the debate over the value, and current validity, of the Shiller’s CAPE ratio, is not new. Critics argue that the earnings component of CAPE is just too low, changes to accounting rules have suppressed earnings, and the financial crisis changed everything," Roberts wrote for Newsmax Finance.

Roberts explained that this was a point made by Wade Slome previously:

“If something sounds like BS, looks like BS, and smells like BS, there’s a good chance you’re probably eyeball-deep in BS. In the investment world, I encounter a lot of very intelligent analysis, but at the same time I also continually step into piles of investment BS. One of those piles of BS I repeatedly step into is the CAPE ratio (Cyclically Adjusted Price-to-Earnings) created by Robert Shiller.”

(Newsmax wires services contributed to this report).