Guides / Rule playground

Rule playground · about 8 min

Reading beliefs

What a rule's number means, how it grows with the margin, and the cases that sit at exactly 0.50 or 0.95.

1. A threshold ladder

   The same SPY reading against five RSI lines, plus a few special cases and one forecast:

   {
     "model": "ora-fin1",
     "state": {
       "symbol": "SPY"
     },
     "questions": {
       "rsi_30": {
         "type": "yes_no",
         "ask": "rsi(C, 14) > 30"
       },
       "rsi_40": {
         "type": "yes_no",
         "ask": "rsi(C, 14) > 40"
       },
       "rsi_50": {
         "type": "yes_no",
         "ask": "rsi(C, 14) > 50"
       },
       "rsi_60": {
         "type": "yes_no",
         "ask": "rsi(C, 14) > 60"
       },
       "rsi_70": {
         "type": "yes_no",
         "ask": "rsi(C, 14) > 70"
       },
       "above_50d": {
         "type": "yes_no",
         "ask": "C > sma(C, 50)"
       },
       "above_95pct": {
         "type": "yes_no",
         "ask": "C > 0.95 * sma(C, 50)"
       },
       "tie": {
         "type": "yes_no",
         "ask": "C >= max(C, 1)"
       },
       "event": {
         "type": "yes_no",
         "ask": "crossdown(C, sma(C, 20))"
       },
       "no_history": {
         "type": "yes_no",
         "ask": "C > sma(C, 2000)"
       },
       "up_week": {
         "type": "yes_no",
         "instructions": "Will the stock be higher in a week?"
       }
     }
   }

   Open this in the Playground

   Question	Rule	Belief
   rsi_30	rsi(C, 14) > 30	0.9145
   rsi_40	rsi(C, 14) > 40	0.5358
   rsi_50	rsi(C, 14) > 50	0.0919
   rsi_60	rsi(C, 14) > 60	0.0537
   rsi_70	rsi(C, 14) > 70	0.0537
   above_50d	C > sma(C, 50)	0.1128
   above_95pct	C > 0.95 * sma(C, 50)	0.9463
   tie	C >= max(C, 1)	0.5
   event	crossdown(C, sma(C, 20))	0.05
   no_history	C > sma(C, 2000)	0.5
   up_week	none: forecast	0.598

   Session of 2026-10-30.

2. It slides, it does not flip

   As the line moves past the reading, the belief moves smoothly from near 0.95 to near 0.05. The yardstick is how much RSI normally moves for SPY over the last 60 sessions, so a few points mean more on a quiet symbol than on a wild one.

3. The fixed points

   • 0.50: exactly on the line (C >= max(C, 1): 0.5) or not known (C > sma(C, 2000): 0.5).
   • 0.95 / 0.05: an event with no margin, such as crossdown(C, sma(C, 20)) (0.05).
   • 0.9463 / 0.0537: a comparison three or more of its usual moves past the line. That is as far as a comparison goes.

4. Belief versus probability

   up_week (0.598) is a forecast: the odds of a higher close in a week. rsi_50 (0.0919) is a fact about today, graded. Use the fact to decide whether a setup is present, and the forecast to decide whether to act.

5. Choosing a line

   For rules, 0.6 and 0.4 are good defaults for "clearly true" and "clearly false". The formula is on Operators and beliefs; lines for forecasts on Choosing thresholds.

Information, not investment advice. Every number on this page is a real response for the session shown; answers change with each session.

What's next

• Rules plus forecasts in one request