Engine Components vs. the Literature

By Rohan Fernandes, Founder · Updated 2026-08-22 · Educational reference, not investment advice

Download the full review: Components vs. the Literature (PDF, 11 pages)

What this review is

A companion to the engine-wide review, prepared the same week against roughly 90 primary sources in four targeted sweeps: chart patterns and regime detection, expiration selection and the option-return term structure, probability-of-profit accuracy and calibration, and volatility-regime-conditioned strategy selection. The subjects are the four components a user actually looks at: Tech Charts, the Expiry Optimizer, the Conviction engine, and the Trade Plan's probability model.

What the evidence supported

The strongest finding is architectural. The entire head-and-shoulders literature arc (Osler and Chang 1995 through Savin, Weller and Zvingelis 2007) converges on one defensible use of chart patterns: a confirmed pattern is a 40-to-60-day directional bias with modest effect size, not an entry signal. That is precisely how the components use them: patterns veto short-strike placement and hand a bias forward, and a technical veto can shrink but never extend an implied-vol-based safety margin, because no study shows technical levels beating option-implied probabilities.

Also validated: the hard 21-day floor on expiration selection (more than 75% of retail index option trades are now same-day expirations, and they lose systematically: Beckmeyer, Branger and Gayda 2023); the gamma-based scoring band (analytic gamma escalation of roughly 2x at 21 days and 5x at 7 days versus 45); the term-structure scoring signs (Vasquez 2017; Johnson 2017); and the choice of N(d2) at the breakeven, rather than delta, as the probability object.

Where the components were on the wrong side of the evidence

• Full-height measured-move targets. Published large-sample hit rates for full pattern-height targets run 46 to 71% depending on the pattern (head-and-shoulders top: 51%; flags: 46%), and the standard prescription is to scale the target by its hit rate. The components projected full height everywhere.
• The Hurst regime vote. Finite-sample estimation of a true random walk averages an exponent near 0.56 at the sample sizes the engine uses, biased toward reading trend, and meaningful tests need thousands of observations (Couillard and Davison 2005). One of three regime votes was mostly noise with a directional lean.
• The skew bonus had sign risk. There is no independently harvestable skew premium (Kozhan, Neuberger and Schneider 2013), and a steep put smirk predicts underperformance of roughly 10.9% per year (Xing, Zhang and Zhao 2010): surface shape is directional information, not a separate premium, so rewarding structures for selling into it had the sign backwards in exactly the cases it rewarded most.
• The straddle window was three times too wide. The documented pre-earnings straddle effect is a 3-to-5-day phenomenon; a 14-day entry gate spends most of its life paying decay in a window the same research shows to be flat to negative (Gao, Xing and Zhang 2018).
• The earnings strike buffer was too thin. Scaled announcement moves are near normal, so a 1.25x expected-move buffer contains only about 79% of events; 1.5x to 2x is the evidence-consistent range (Dubinsky and Johannes lineage).
• Probability of profit was missing the smile-slope term. The exact option-implied probability of finishing in the money is the digital price, which includes a vega-times-smile-slope correction beyond the strike's own implied volatility (Breeden and Litzenberger 1978). At typical index-put skew the omission is worth several probability points at the deltas where short strikes live.

What changed as a result

v3.97.0 shipped the review's actionable tiers: the smile-slope correction is now computed by finite difference from each chain's own smile, so the direction and size come from the observed surface rather than an assumption; displayed pattern targets are scaled to published hit rates while vetoes keep the conservative full height; the earnings buffer moved from 1.25x to 1.75x expected move; the straddle catalyst gate tightened from 14 calendar days to 5 trading days; the skew bonus was repurposed into a directional caution modifier; the Hurst vote was removed from the range regime; gamma-wall placement nudges were demoted to informational after a pre-registered test found no strike-local effect; busted patterns now flip their bias instead of merely voiding it; VIX regime labels gained hysteresis so a 0.1-point print cannot flip them; and the calibration report now tests short puts and short calls separately and states its minimum detectable effect at current sample size.

What was deliberately not adopted

The 37-day center of the expiration score kept its honest framing: the literature shows premium per unit of risk rising monotonically toward shorter expirations, so 37 days is a gamma-and-frictions optimum for an unhedged seller, not a premium optimum, and the interface says so. Condor return expectations are set off the modern subsample of the index condor benchmark, which was roughly flat for 2010 to 2019, not the stronger pre-2010 record.

Selected sources

• Savin, G., Weller, P. and Zvingelis, J. (2007). The Predictive Power of Head-and-Shoulders Price Patterns in the U.S. Stock Market. Journal of Financial Econometrics.
• Bulkowski, T. (2005). Encyclopedia of Chart Patterns, 2nd ed. Wiley (practitioner; measured-move hit rates).
• Couillard, M. and Davison, M. (2005). A Comment on Measuring the Hurst Exponent of Financial Time Series. Physica A.
• Beckmeyer, H., Branger, N. and Gayda, L. (2023). Retail Traders Love 0DTE Options... But Should They? SSRN.
• Dew-Becker, I., Giglio, S., Le, A. and Rodriguez, M. (2017). The Price of Variance Risk. Journal of Financial Economics.
• Kozhan, R., Neuberger, A. and Schneider, P. (2013). The Skew Risk Premium in the Equity Index Market. Review of Financial Studies.
• Xing, Y., Zhang, X. and Zhao, R. (2010). What Does the Individual Option Volatility Smirk Tell Us About Future Equity Returns? JFQA.
• Gao, C., Xing, Y. and Zhang, X. (2018). Anticipating Uncertainty: Straddles Around Earnings Announcements. JFQA.
• Breeden, D. and Litzenberger, R. (1978). Prices of State-Contingent Claims Implicit in Option Prices. Journal of Business.
• Heston, S., Jones, C., Khorram, M., Li, S. and Mo, H. (2023). Option Momentum. Journal of Finance.

The complete bibliography is in the full review: Components vs. the Literature (PDF). Research commentary, not investment advice.