The two charts below offer clues for evaluating the risk of profit margin squeeze in the current economy. One is the ratio of crude to finished goods in the Producer Price Index. The other is an indicator constructed from two data series in the Philadelphia Fed's Business Outlook Survey through today's release. It is the spread between the Philly Fed's prices paid (input costs) and received (prices charged) data.

A major risk factor for margin squeeze had been the increase in commodity prices over the past several months with the price of oil and gasoline as the dominant factor. Commodity prices have moderated, but the squeeze remains in evidence.

So let's take a broader view of these two indicators by viewing them within the context of inflation as measured by the Consumer Price Index. As the first chart clearly shows, the all-time high in the PPI crude-to-finished-goods ratio was in July 2008, the same month that crude oil and gasoline prices in the U.S. hit their all-time highs. The previous ratio high was in the summer of 1973, a few months before the outbreak of the October Arab-Israeli War and the Oil Embargo. Inflation had already been rising in a series of waves since the mid-1960s. But Middle-East events of 1973 were the primary trigger for the nearly ten years of stagflation that followed.

The February 2012 ratio is at the 97th percentile of the 779 data points in this series. The interim high since the 2008 peak was the 99th percentile in April of last year, but on a percentile basis, the ratio has been essentially stalled in the upper 90th percentiles since December 2010, hovering between the 96th and 99th percentiles.

The Philly Fed Prices Paid Minus Prices Received Index is an extremely volatile series, which I've illustrated by using dots for the monthly data points. The volatility is so great that the value for any specific month can't be taken very seriously. However, to highlight the underlying pattern, I've included a 12-month moving average (MA). The date callouts show that the comparable levels in the past were associated with inflationary peaks. The latest ratio is at the 71st percentile of the 526 monthly data points in this series, up from the 59th percentile last month. The 12-month MA is now 24.1% off the all-time high set in March of last year, but that's still in the 81st percentile of the 12-month MA series.

By official government metrics, the CPI and PCE, inflation is not a near-term threat. In fact, the Federal Reserve has worked hard in the wake of the Financial Crisis to raise the level of core inflation, and not without success, as the latest core CPI (ex food and energy) is now above the 2% target rate at 2.23%. However, the Fed uses the PCE core index as their favored metric, which is at the lower level of 1.85% (latest data through December).

Of course, there are many differences between the inflationary decade of the 1970s and the present, not least of which is the rate of unemployment. In August 1973 (first chart above), unemployment was at 4.8%. The latest unemployment number from the Bureau of Labor Statistics is 8.3%. Also, U.S. demographics today are quite different. The oldest Boomers were turning 27 in 1973. They were at the beginning of their careers with decades of wage increases in their expectations. This year they are turning 65, and many are already on Social Security as their main source of income.

At present, in light of the unemployment rate and the ongoing demographic shift, rises in commodity prices probably pose more risk of continuing margin squeeze than run-away inflation. Some degree of cost-push inflation may be a near-term risk, but the demand-pull inflation we saw in the 1970s is difficult to envision in the U.S. economy of this decade.

On the other hand, the volatility of commodity prices, especially oil, keeps the topic of profit margin squeeze on the table.