Price oscillator from two moving averages

Two averages become one oscillator

A price oscillator is constructed as a shorter-duration moving average minus a longer-duration moving average. Those two averages are the only inputs. The difference may be stated as a points difference or as a percentage difference of the longer average. The averages may be simple, weighted, exponential, or variable. The worked construction uses simple averages.

The zero line holds the overlay

Plotting the difference recasts the longer average as a zero line, so the shorter average appears above or below that line. Distance from zero and the crossing points are described as carrying the same information as the two averages overlaid on price. A moving-average crossover is the shorter average crossing the longer average, shown on the oscillator as a crossing of the zero line.

A fixed crossing rule

The mechanical rule tied to this construction treats a shorter-average crossing from below the zero line to above it as a buy signal and a crossing from above to below as a sell signal. A mechanical trading system maps those crossings into entry, exit, and abstention without discretionary overrides. In this archive workflow the oscillator remains one confirming tool inside a broader mechanical procedure, not a complete standalone system.

Lookback pairs change speed and lag

Lookbacks are chosen by security and decision horizon. Commodity applications typically use shorter increments than stock applications. Often-cited lookback pairs include 1 and 10 or 1 and 25 periods, 5 and 20 or 10 and 40 periods, and 50 and 200 periods.

Shorter lookbacks produce faster, more frequent zero-line crossings and can reverse so often in a narrow volatile range that brokerage commissions consume the moves being traded. That rapid opposite crossing is the whipsaw most common with short lookbacks. Longer lookbacks reduce that rapid reversal but lag tops and bottoms.

Illustrated crossings

On one illustrated daily series, the 1-and-25, 10-and-40, and 50-and-200 lookback pairs all produced a buy-side zero-line crossing in November 1993. The number of crossings fell as the lookbacks lengthened. The 50-and-200-day pair is treated as interchangeable with a 10-and-40-week pair.

On a second illustrated series, both a 10-and-40-day pair and a 50-and-200-day pair produced a buy-side crossing near the end of 1993, with more oscillation on the shorter pair during the February-to-May interval.

Confirmation is not automatic

The same construction can issue a sell only after a large decline is already underway. On a third series both the 10-and-40-day and 50-and-200-day versions produced signals that were largely opposite subsequent price movement, with the shorter pair often crossing after a significant move had already occurred.

One tool inside a larger procedure

The archive presents the oscillator as one confirming tool inside a broader mechanical procedure rather than as a complete standalone system. It states that no single mechanical trading tool is sufficient by itself.