Numbers can lie -- but they're the best first step in determining whether a stock is a buy. In this series, we use some carefully chosen metrics to size up a stock's true value based on the following clues:

  • The current price multiples.
  • The consistency of past earnings and cash flow.
  • How much growth we can expect.

Let's see what those numbers can tell us about how cheap energy equipment maker National Oilwell Varco (NYSE: NOV) might be.

The current price multiples
First, we'll look at most investors' favorite metric: the P/E ratio. It divides the company's share price by its earnings per share -- the lower, the better.

Then, we'll take things up a notch with a more advanced metric: enterprise value to unlevered free cash flow. This divides the company's enterprise value (basically, its market cap plus its debt, minus its cash) by its unlevered free cash flow (its free cash flow, adding back the interest payments on its debt). Like the P/E, the lower this number is, the better.

Analysts argue about which is more important -- earnings or cash flow. Who cares? A good buy ideally has low multiples on both.

National Oilwell Varco has a P/E ratio of 12.7 and an EV/FCF ratio of 19.8 over the trailing 12 months. If we stretch and compare current valuations to the five-year averages for earnings and free cash flow, National Oilwell Varco has a P/E ratio of 15.8 and a five-year EV/FCF ratio of 15.2.

A one-year ratio under 10 for both metrics is ideal. For a five-year metric, under 20 is ideal.

National Oilwell Varco has a mixed performance in hitting the ideal targets, but let's see how it compares against some competitors and industry mates. 

Company

1-Year P/E

1-Year EV/FCF

5-Year P/E

5-Year EV/FCF

National Oilwell Varco

12.7

19.8

15.8

15.2

Tesco (Nasdaq: TESO)

NM

9.6

22.1

NM

Weatherford International (NYSE: WFT)

NM

NM

18.0

NM

Baker Hughes (NYSE: BHI)

54.5

NM

14.7

156.4

Source: Capital IQ, a division of Standard & Poor's; NM = not meaningful.

Numerically, we've seen how National Oilwell Varco's valuation rates on both an absolute and relative basis. Next, let's examine ...

The consistency of past earnings and cash flow
An ideal company will be consistently strong in its earnings and cash flow generation.

In the past five years, National Oilwell Varco's net income margin has ranged from 7.9% to 13.9%. In that same time frame, unlevered free cash flow margin has ranged from 6% to 16.6%.

How do those figures compare with those of the company's peers? See for yourself:



Source: Capital IQ, a division of Standard & Poor's; margin ranges are combined.

Additionally, over the last five years, National Oilwell Varco has tallied up five years of positive earnings and five years of positive free cash flow.

Next, let's figure out ...

How much growth we can expect
Analysts tend to comically overstate their five-year growth estimates. If you accept them at face value, you will overpay for stocks. But while you should definitely take the analysts' prognostications with a grain of salt, they can still provide a useful starting point when compared to similar numbers from a company's closest rivals.

Let's start by seeing what this company's done over the past five years. In that time period, National Oilwell Varco has put up past EPS growth rates of 37.1%. Meanwhile, Wall Street's analysts expect future growth rates of -12.3%.

Here's how National Oilwell Varco compares it its peers for trailing five-year growth (Tesco and Weatherford don't have meaningful growth rates because of unprofitability):



Source: Capital IQ, a division of Standard & Poor's; EPS growth shown.

And here's how it measures up with regard to the growth analysts expect over the next five years:



Source: Capital IQ, a division of Standard & Poor's; estimates for EPS growth.

The bottom line
The pile of numbers we've plowed through has shown us how cheap shares of National Oilwell Varco are trading, how consistent its performance has been, and what kind of growth profile it has -- both on an absolute and a relative basis.

The more consistent a company's performance has been and the more growth we can expect, the more we should be willing to pay. We've gone well beyond looking at a 12.7 P/E ratio.

National Oilwell Varco dominates its industry -- providing equipment to the oil and natural gas industry – and it's selling for reasonable multiples. However, you may be taken aback by analysts' negative growth estimates for the next five years. That bothered me, too, but upon digging in, the estimates are based on just three analysts, and the average is dragged down by an outlier. Looking at Yahoo! Finance's numbers (rather than Capital IQ's), I see more analysts weighing in and an average growth estimate of 7.5%.

Given this, and given its status as a Stock Advisor pick, National Oilwell Varco is a company worth looking into. If you agree, continue your due diligence process until you're confident that the initial numbers aren't lying to you.

Click here to add National Oilwell Varco to My Watchlist, and find all of our Foolish analysis on this stock.