The Zig Zag indicator filters out changes in an
underlying plot (e.g., a security's price or another indicator) that are
less than a specified amount. The Zig Zag indicator only shows
significant changes.
Interpretation
The Zig Zag indicator is used primarily to help you
see changes by punctuating the most significant reversals.
It is very important to understand that the last
"leg" displayed in a Zig Zag chart can change based on changes in the
underlying plot (e.g., prices). This is the only indicator in this book
where a change in the security's price can change a previous value of
the indicator. Since the Zig Zag indicator can adjust its values based
on subsequent changes in the underlying plot, it has perfect hindsight
into what prices have done. Please don't try to create a trading system
based on the Zig Zag indicator--its hindsight is much better than its
foresight!
In addition to identifying significant prices
reversals, the Zig Zag indicator is also useful when doing Elliot Wave
counts.
For additional information on the Zig Zag indicator,
refer to Filtered Waves by Arthur Merrill.
Example
The following chart shows the 8% Zig Zag indicator
plotted on top of Mattel's bar chart.
This Zig Zag indicator ignores changes in prices
that are less than 8%.
Calculation
The Zig Zag indicator is calculated by placing
imaginary points on the chart when prices reverse by at least the
specified amount. Straight lines are then drawn to connect these
imaginary points.