Numbers can lie -- yet 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.
  • The amount of growth we can expect.

Let's see what those numbers can tell us about how expensive or cheap Boston Scientific (NYSE: BSX) might be.

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

Then we'll take things up a notch with a more advanced metric: enterprise value to unlevered free cash flow. This tool 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). As with 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.

Boston Scientific has a negative P/E ratio and an EV/FCF ratio of 55.1 over the trailing 12 months. If we stretch and compare current valuations with the five-year averages for earnings and free cash flow, we see that Boston Scientific has a negative P/E ratio and a five-year EV/FCF ratio of 16.7.

A positive one-year ratio of less than 10 for both metrics is ideal. For a five-year metric, less than 20 is ideal.

Boston Scientific has a mixed performance in hitting the ideal targets, but let's see how it stacks up against some of its competitors and industry mates. 

Company

1-Year P/E

1-Year EV/FCF

5-Year P/E

5-Year EV/FCF

Boston Scientific NM 55.1 NM 16.7
Abbott Labs (NYSE: ABT) 16.9 11.4 19.0 15.8
Medtronic (NYSE: MDT) 13.0 12.7 16.0 15.1
Johnson & Johnson (NYSE: JNJ) 12.2 10.6 13.5 11.7

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

Numerically, we've seen how Boston Scientific'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, Boston Scientific's net income margin has ranged from -45.7% to -5.9%. In that same time frame, unlevered free cash flow margin has ranged from 3.8% to 22.7%.

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

Bsxmarginrangesv

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

In addition, over the past five years, Boston Scientific has tallied up no 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 even though you should definitely take the analysts' prognostications with a grain of salt, they can still provide a useful starting point when compared with similar numbers from a company's closest rivals.

Let's start by seeing what this company's done over the past five years. During that time, Boston Scientific has put up losses that render its past EPS growth rates meaningless. However, Wall Street's analysts expect future growth rates of 7.0%.

Here's how Boston Scientific compares with its peers for trailing five-year growth:

Bsxtrailing

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:

Bsx

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 the price multiples that shares of Boston Scientific are trading at, the volatility of its operational performance, 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 negative P/E ratio, and we see no years of positive earnings in the last five years. However, when we look at enterprise value to free cash flow over a five-year period, Boston Scientific looks quite reasonable. We also see moderate expectations for future growth. But these are just the initial numbers. If you find Boston Scientific's numbers or story compelling, don't stop here. Continue your due-diligence process until you're confident one way or the other. As a start, add it to My Watchlist to find all of our Foolish analysis.

Anand Chokkavelu owns shares of Johnson & Johnson, which is a recommendation of Motley Fool Inside Value and Motley Fool Income Investor. Motley Fool Options has recommended a diagonal call position on Johnson & Johnson. The Fool owns shares of Abbott Laboratories, Johnson & Johnson, and Medtronic. Motley Fool Alpha LLC owns shares of Abbott Laboratories and Johnson & Johnson. Try any of our Foolish newsletter services free for 30 days. We Fools don't all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.