SMA stands for simple moving average.
Read from the start: chapter 1 The RuleLeveraged ETFs can lose a large part of their value in a short time.
Backtest on historical data: shows what the rule would have done, not what it will do. Not investment advice.
Three periods that show how the rule feels. The website computes the curves from real product prices; the text only tells what happened.
The rule exited at the end of February, before the lowest point, and avoided the largest part of the crash. Afterwards the index stayed close to the line for a long time.
The repeated switches in March and then from May to June, each a re-entry and an exit close together, cost every time. Only at the end of June did the rule stay in the market again.
At the end of the period Holding was ahead, not because the filter had missed the crash, but because of the false signals at the line. Holding itself ended below the start at the leveraged product, even though the index was slightly above it. The difference is the volatility drag.
2022 went differently. The decline stretched over months, with many interim recoveries.
That is exactly what the rule is built for: it left the market early in the year and stayed out for most of it while the market kept giving way. A leveraged holding would have suffered particularly in this phase, because turbulent declines let the volatility drag work at full strength.
It was not free of cost. Every interim recovery raised the question whether the rule had exited too early, and more than one re-entry ended in the next exit shortly after.
The third example is the most unpleasant one, because it is the most common. The broad US market moved sideways for a year and crossed the line several times.
The rule switched accordingly often: sell, buy back higher shortly after, sell again. Each of those cost the bid-ask spread, and in a taxable account tax on the realised gains on top.
Holding would have come through this period more calmly. That is not a defect of the rule but the price it charges for the protection in the long declines.