An exponential moving average (EMA) responds to prices much more quickly than a simple moving average. This is because the EMA gives more weight to the latest data rather than older data. It's a good indicator for the short term and a great method to catch short term trends, which is why traders use both simple and exponential moving averages simultaneously for entry and exits. Nevertheless, it too can leave data behind.

## The Problem With Moving Averages

In his research, McGinley found moving averages had many problems. In the first place, they were inappropriately applied. Moving averages in different periods operate with varying degrees in different markets. For example, how can one know when to use a 10-day, 20-day, or a 50-day moving average in a fast or slow market? In order to solve the problem of choosing the right length of the moving average, the McGinley Dynamic was built to automatically adjust to the current speed of the market.

McGinley believes moving averages should only be used as a smoothing mechanism rather than a trading system or signal generator. It is a monitor of trends. Further, McGinley found moving averages failed to follow prices since large separations frequently exist between prices and moving average lines. He sought to eliminate these problems by inventing an indicator that would hug prices more closely, avoid price separation and whipsaws, and follow prices automatically in fast or slow markets.

## McGinley Dynamic Formula

This he did with the invention of the McGinley Dynamic. The formula is:

$ MD=MD+k×N×(MD$

$Close )$

$Close−MD where:MD=Current McGinley DynamicMD=Previous McGinley DynamicClose=Closing pricek=(Constant 60% of selected period N)N=Moving average period $

The McGinley Dynamic looks like a moving average line, yet it is actually a smoothing mechanism for prices that turns out to track far better than any moving average. It minimizes price separation, price whipsaws, and hugs prices much more closely. And it does this automatically as a factor of its formula.

Because of the calculation, the Dynamic Line speeds up in down markets as it follows prices yet moves more slowly in up markets. One wants to be quick to sell in a down market, yet ride an up market as long as possible. The constant N determines how closely the Dynamic tracks the index or stock. If one is emulating a 20-day moving average, for instance, use an N value half that of the moving average, or in this case 10.

It greatly avoids whipsaws because the Dynamic Line automatically follows and stays aligned to prices in any market—fast or slow—like a steering mechanism of a car that can adjust to the changing conditions of the road. Traders can rely on it to make decisions and time entrances and exits.

## The Bottom Line

McGinley invented the Dynamic to act as a market tool rather than as a trading indicator. But whatever it's used for, whether it is called a tool or indicator, the McGinley Dynamic is quite a fascinating instrument invented by a market technician that has followed and studied markets and indicators for nearly 40 years. In creating the Dynamic, McGinley sought to create a technical aid that would be more responsive to the raw data than simple or exponential moving averages.

Investopedia's *Technical Analysis Strategies for Beginners *guide offers more information on indicators and market tools.

### Compete Risk Free with $100,000 in Virtual Cash

Put your trading skills to the test with our FREE Stock Simulator. Compete with thousands of Investopedia traders and trade your way to the top! Submit trades in a virtual environment before you start risking your own money. Practice trading strategies so that when you're ready to enter the real market, you've had the practice you need. Try our Stock Simulator today >>