THE 5-YEAR-OLD VERSION
The market zig-zags like a puppy on a walk, but the walk still goes somewhere. A trend is the direction of the walk. A moving average is a smooth line showing where the puppy has been on average over the last stretch, so you can see the walk without the zig-zags.
What a moving average is
A 50-day moving average is the average of the last 50 daily closes. Each day it drops the oldest and adds the newest, so it "moves". The 200-day is the same over 200 days. The longer the average, the smoother and slower it is.
Moving averages lag: they describe the past and react late. Traders often read "price above the 200-day average" as an uptrend and "below" as a downtrend.
A fair test: the 200-day rule
Rule: hold the Nifty 50 only while it closes above its 200-day average (trading the next day). When it is below, sit in cash. Tested from July 2008 to April 2026:
| Always invested | 200-day rule | |
|---|---|---|
| Total price return | +512% | +226% |
| Worst fall from a high | -45% | -23% |
| Time invested | 100% | 73% |
| Number of switches | 0 | 144 |
What this test shows, and what it does not
The rule roughly halved the worst fall (-45% to -23%) but gave up more than half the total gain, and flipped 144 times (about 72 round trips), each of which would cost money and, outside a retirement account, trigger tax. It is one market, one rule, with the benefit of hindsight. Rules that look great on past data often fail on new data.
That is the real lesson of technical analysis: tools like this are trade-offs, not magic. They change the shape of your ride (smaller falls, smaller gains, more activity), which may suit one person and not another.