20-Week Average Test
60 test-and-hold events since 1950; next 4 weeks higher 63% against 61% for any week, next 13 weeks 71% against 67%.
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After twelve straight weeks above its 20-week moving average, the S&P 500 dips to touch it and closes the week back above. A circulated rule says the next three weeks to two months were higher every time, based on eleven events since 2010. This rebuilds it on the full history back to 1928, with the base rate beside every number and the sample split before and after 1990 to see whether the edge survives data it was never fitted to. If it is no better than a random week, it says so.
- 60 signals since 1928-01-01.
- 60 test-and-hold events since 1950; next 4 weeks higher 63% against 61% for any week, next 13 weeks 71% against 67%.
When to run this study
Run when the S&P 500 has been trending above its 20-week average for a quarter or more and a pullback is bringing it back to that line. A touch that closes the week back above the average is the setup; the close that week is the level to watch. The study shows how often the next weeks were higher against any random week, on the full history back to 1928 and split before and after 1990 so the circulated post-2010 claim can be checked on data it was never fitted to.
Historical results
After a held test (60 events) against any week
| Forward | N | Higher | Median | Worst | Any week: higher | Any week: median | Any week after a 12-week run: higher | Edge (pts) |
|---|---|---|---|---|---|---|---|---|
| 1W | 60 | 51.70 | 0.16 | -3.80 | 56.70 | 0.30 | 56.80 | -5.10 |
| 2W | 60 | 51.70 | 0.31 | -5.10 | 59.40 | 0.56 | 58.30 | -7.70 |
| 3W | 59 | 57.60 | 0.69 | -11.70 | 60.70 | 0.82 | 60.70 | -3.10 |
| 4W | 59 | 62.70 | 1.23 | -22.50 | 61.30 | 1.10 | 63.60 | 1.40 |
| 8W | 59 | 72.90 | 2.64 | -24.40 | 63.80 | 1.83 | 67.40 | 9.10 |
| 13W | 59 | 71.20 | 2.90 | -21.30 | 66.80 | 2.69 | 71.70 | 4.40 |
| 26W | 59 | 72.90 | 4.47 | -19.40 | 70.70 | 5.10 | 77.20 | 2.20 |
| 52W | 57 | 68.40 | 6.86 | -19.20 | 74.60 | 10.53 | 79.30 | -6.20 |