HoldoutLabs
Scientific audits for trading strategies
Strategy Fragility Audit
Report 831792d60c51 · 2026-09-25 18:23 UTC
holdout-audit 0.3.0 · rubric v1.1

Batch 1: MACD (TradingView built-in strategy) on SPY

TradingView's built-in 'MACD Strategy' with its default settings, long and short as it ships, on SPY daily bars. Benchmark: buy-and-hold SPY. Part of Indicator Audit Batch 1 (20 audits, one sealed preregistration, Holm across the batch).

Executive summary

Fragility grade
F
1/16 points (6%)

Very fragile. The backtest shows no robust edge over its benchmark once selection, holdout and stability are accounted for. The grade measures how fragile the historical evidence is. It is not a forecast and not a recommendation.

Declared objective: beat the benchmark, declared by the client on 2026-09-25T18:21:27Z (declaration SHA-256 35b4d77e284614c1…).

Benchmark: buy-and-hold of the traded asset. This is the rubric v1.1 default. The strategy did not beat its benchmark under the rubric definition, so the grade is at most C.

Excess Sharpe vs benchmark (95% CI)
-0.48 [-0.82, -0.14]
Excess return a year
-14.5%
Absolute Sharpe
-0.13
Deflated Sharpe (N=48)
<0.001
PBO (CSCV)
0.320
Holdout excess Sharpe (in → out)
-0.45 → -0.55
Max drawdown
80.0%
Buy-and-hold Sharpe, same period
0.65

Checks that failed: Selection-adjusted significance vs benchmark (Deflated Sharpe); Multiple-testing haircut vs benchmark (Harvey-Liu); Beats the benchmark after data snooping (Hansen SPA); Holdout degradation (excess Sharpe); Period and regime stability (vs benchmark); Transaction-cost headroom (absolute); Parameter plateau (absolute).

Scorecard

CheckResultValueRule
Selection-adjusted significance vs benchmark (Deflated Sharpe)FAILDSR 0.000 (N = 48)PASS DSR >= 0.95; CAUTION >= 0.80; else FAIL (on excess returns)
Probability of backtest overfitting (CSCV)CAUTIONPBO 0.320 (12870 splits)PASS PBO <= 0.20; CAUTION <= 0.50, or PBO > 0.50 with P(OOS excess SR < 0) <= 0.10; else FAIL
Multiple-testing haircut vs benchmark (Harvey-Liu)FAILadj. p 1.0000 (BHY)PASS one-sided adjusted p <= 0.05; CAUTION <= 0.10; else FAIL (excess-return t-statistic; evidence for the strategy only)
Beats the benchmark after data snooping (Hansen SPA)FAILSPA p 1.000; RC p 1.000PASS p <= 0.05; CAUTION <= 0.10; else FAIL
Holdout degradation (excess Sharpe)FAILexcess SR -0.45 -> -0.55PASS holdout and in-sample excess SR > 0 and holdout >= 50% of in-sample; CAUTION holdout excess SR > 0; else FAIL
Period and regime stability (vs benchmark)FAIL18% of years aheadPASS >= 60% of years ahead of benchmark and excess SR > 0 in every volatility tercile; CAUTION >= 50%; else FAIL
Transaction-cost headroom (absolute)FAILbreak-even -3.6 bpsPASS break-even cost >= 20 bps per unit traded; CAUTION >= 5 bps; else FAIL (absolute)
Parameter plateau (absolute)FAILneighbours n/a% of chosenPASS neighbour SR >= 70% of chosen SR; CAUTION >= 40%; else FAIL, or FAIL if chosen SR <= 0 (absolute)

How the grade is set (Holdout Labs Fragility Rubric v1.1, sealed before this report was produced). PASS = 2 points, CAUTION = 1, FAIL = 0; N/A checks are excluded. Share of available points: A ≥ 85%, B ≥ 70%, C ≥ 55%, D ≥ 40%, otherwise F. Hard caps: Objective cap (beat the benchmark): if the strategy does not beat its benchmark (SPA check FAIL, or annualised mean excess return <= 0), the grade is at most C. Objective cap (reduce drawdown): if the drawdown reduction is not robust (drawdown check FAIL) or the declared return-cost tolerance is breached (tolerance check FAIL), the grade is at most C. Selection cap: if the deflated check FAILS, the grade is at most C. Overfitting cap: if the PBO check FAILS, the grade is at most D. Disclosure cap: if the number of variants tried was not declared and no variant matrix was supplied, the grade is at most B.

What was audited

Audited variant: fast=12|slow=26|signal=9|mode=long_short. Rule (as preregistered): MACD = EMA(close, fast) - EMA(close, slow); delta = MACD - EMA(MACD, signal); long on crossover(delta, 0), short on crossunder(delta, 0) (market orders). Grid: 48 variants (see the preregistration).
Sample1994-01-03 to 2026-09-24 (8237 periods, 252 per year)
Variants tried (N)48 · variant matrix of 48 columns supplied
Base-case cost2 bps per unit traded (one way)
Holdout split2017-01-03
Compound annual return, strategy (net)-4.1%
Buy-and-hold of the underlying, same periodcompound annual return 10.9%; annualised Sharpe 0.65; max drawdown 55.2%

Results in detail

Growth of 1 (log scale)holdout0.51251020199419982002200620102014201820222026StrategyBuy and hold
Growth of 1 on a log scale, net of base-case costs, with buy-and-hold of the underlying in grey. The shaded area is the holdout period.

1. Sharpe ratio and its uncertainty

Rubric checks use the excess series (strategy minus buy-and-hold of the traded asset); the absolute series is shown for reference.

Excess over benchmarkAbsolute
Annualised Sharpe (sqrt-time scaling)-0.481-0.130
Annualised Sharpe (Lo 2002 autocorrelation-adjusted)-0.666-0.173
Standard error, annualised (non-normal)0.1750.175
Standard error per period: IID-normal / non-normal0.0110 / 0.01100.0110 / 0.0110
Skewness / kurtosis-0.13 / 29.00-0.10 / 14.59
Probabilistic Sharpe ratio vs 00.00300.2279
Minimum track record for 95% confidence∞ years∞ years
Annualised mean / volatility-14.5% / 30.2%-2.4% / 18.7%

2. The variant-count effect (Deflated Sharpe)

Deflated Sharpe ratio against number of variants tried00.20.40.60.811: 0.00312: 0.00225: 0.001510: 0.0011020: 0.0002048: 0.0004850: 0.00050100: 0.000100200: 0.000200500: 0.0005001000: 0.0001000variants tried (log scale)
The same backtest, judged as the best of N tries. The dark dot is the declared N = 48; the dashed line is the 0.95 pass mark. Computed on the excess Sharpe over the benchmark. The more variants tried, the higher the bar.
N triedNoise hurdle (annual excess SR)DSR
10.0000.0030
20.0300.0018
50.0690.0009
100.0910.0006
200.1090.0004
480.1300.0002
500.1310.0002
1000.1450.0002
2000.1590.0001
5000.175<0.0001
10000.187<0.0001

Dispersion of trial Sharpe ratios used: 0.057 (annualised standard deviation), estimated from the variant matrix.

3. Probability of backtest overfitting (CSCV)

Logit of the in-sample winner's out-of-sample rank-202median
PBO0.320
Splits (blocks)12870 (16)
Variants48
P(IS winner trails benchmark out of sample)1.000
Median OOS excess Sharpe of IS winner (annual)-0.55
Degradation slope (OOS on IS)-0.88

Histogram of logit ranks: values left of the dashed line are splits where the in-sample winner finished at or below the out-of-sample median (logit 0).

4. Multiple-testing haircut

t-statistic (excess SR x sqrt(years))-2.75
p-value, single test0.99701
Bonferroni p (48 tests)1.00000
Sidak p1.00000
Holm p1.00000
BHY p1.00000
Haircut excess Sharpe (Bonferroni)-0.000 (100% haircut)
Haircut excess Sharpe (BHY)-0.000

5. Reality Check and SPA

Benchmarkbuy-and-hold of the traded asset
Variants in the test48
Best mean excess return (annualised)-7.27%
White Reality Check p1.000
Hansen SPA p (consistent / lower / upper)1.000 / 1.000 / 1.000
Bootstrapstationary, 1000 draws, mean block 20

6. Holdout degradation

PeriodsAnnualised excess Sharpe
In-sample (before 2017-01-03)5792-0.454
Holdout2445-0.545
Holdout / in-samplen/a
Consistency p-value0.778

7. Period and regime stability

Return minus benchmark return, by calendar year-50%-25%0%25%50%1994: 7.7%1995: -42.2%1996: -27.2%1997: -47.7%1998: -36.6%1999: -54.6%2000: -10.7%2001: 11.2%2002: 41.1%2003: -35.3%2004: -10.8%2005: -6.8%2006: -37.8%2007: 2.4%2008: 53.6%2009: -40.0%2010: -10.9%2011: -6.6%2012: -20.9%2013: -35.3%2014: -10.3%2015: -18.0%2016: -6.9%2017: -24.6%2018: -1.9%2019: -23.6%2020: -1.9%2021: -43.2%2022: 27.4%2023: -25.7%2024: -30.1%2025: -35.0%2026: -15.6%19941997200020032006200920122015201820212024
Strategy compounded return minus benchmark compounded return, by year: ahead in 6 of 33 years (absolute return positive in 11).
Volatility regime (trailing 21-day, lagged)PeriodsAnnualised mean excessAnnualised excess Sharpe
low vol2739-15.5%-0.91
mid vol2738-6.4%-0.26
high vol2739-21.4%-0.50

8. Transaction-cost sensitivity

One-way cost (bps per unit traded)0125102050
Annualised Sharpe-0.08-0.11-0.13-0.20-0.32-0.55-1.22
Annualised mean return-1.6%-2.0%-2.4%-3.8%-5.9%-10.3%-23.4%

Turnover 43.6 units per year; break-even cost -3.6 bps.

9. Parameter sensitivity

Annualised Sharpe across the parameter gridslow ↓ / fast →581217-0.06slow=17, fast=5: -0.060-0.01slow=17, fast=8: -0.0070.04slow=17, fast=12: 0.03621-0.02slow=21, fast=5: -0.0180.01slow=21, fast=8: 0.0140.06slow=21, fast=12: 0.05626-0.03slow=26, fast=5: -0.0260.03slow=26, fast=8: 0.0300.07slow=26, fast=12: 0.07235-0.02slow=35, fast=5: -0.0200.06slow=35, fast=8: 0.0580.07slow=35, fast=12: 0.074
Annualised Sharpe by parameter pair (averaged over signal, mode). The outlined cell holds the chosen variant.

Chosen variant fast=12|slow=26|signal=9|mode=long_short ranks 25 of 48. Grid median Sharpe 0.01, best 0.44; 50% of cells positive; neighbour ratio n/a.

10. Drawdown distribution

Bootstrap distribution of maximum drawdown50%60%70%80%90%realised
Maximum drawdown in 1000 stationary-bootstrap resamples. Realised: 80.0%; median 83.7%; 95th percentile 95.4%. 64% of resamples were worse than the realised drawdown.

What is fragile, and how to test the fix

FAIL Selection-adjusted significance vs benchmark (Deflated Sharpe)

Excess Sharpe over buy-and-hold of the traded asset (total return): -0.48 a year over 32.7 years. After allowing for 48 variant(s) tried, the best-of-N noise hurdle is an annualised excess Sharpe of 0.13; the probability that the true excess Sharpe exceeds it is 0.000.

How to test a fix: Declare every variant you tried (including abandoned ones), then re-test on data you have not looked at: a sealed forward period or a later holdout. A DSR that only passes at N = 1 is not evidence.

CAUTION Probability of backtest overfitting (CSCV)

Across 12870 combinatorial in-sample/out-of-sample splits of 48 variants, ranked by excess Sharpe, the in-sample winner ranked in the bottom half out of sample 32.0% of the time and trailed the benchmark out of sample 100.0% of the time.

How to test a fix: Shrink the search: fewer free parameters, coarser grids, rules fixed from theory before looking at results. Then re-run CSCV on the smaller family; PBO should fall.

FAIL Multiple-testing haircut vs benchmark (Harvey-Liu)

Excess-return t-statistic -2.75 (single-test p 0.9970). Adjusted for 48 tests (BHY), p = 1.0000; the Bonferroni-haircut excess Sharpe is -0.00.

How to test a fix: A longer sample raises the t-statistic without new selection: extend the test to earlier or later data the rule was not designed on, keeping the rule frozen.

FAIL Beats the benchmark after data snooping (Hansen SPA)

Benchmark: buy-and-hold of the traded asset (total return). Testing whether the best of 48 variant(s) beats it in mean return, with a stationary bootstrap (1000 draws, mean block 20 periods): Hansen SPA p = 1.000, White Reality Check p = 1.000.

How to test a fix: If the rule's value is lower risk rather than higher return, state that claim before testing it (e.g. drawdown or volatility against the benchmark) and test it on unseen data.

FAIL Holdout degradation (excess Sharpe)

In-sample (before 2017-01-03) annualised excess Sharpe -0.45; holdout -0.55 over 2445 periods. Consistency p-value 0.778 (low values mean the holdout is unlikely to share the in-sample excess Sharpe).

How to test a fix: Lock a fresh holdout before any further tuning, or run a sealed forward trial with preregistered pass criteria; only data you have not seen can confirm a fix.

FAIL Period and regime stability (vs benchmark)

The strategy's compounded return beat the benchmark's in 6 of 33 calendar years. Annualised excess Sharpe by volatility tercile: low vol -0.91, mid vol -0.26, high vol -0.50.

How to test a fix: Check whether the edge over the benchmark is concentrated in a few years or one regime; if so, state that regime as part of the hypothesis and test it on a period the rule has not seen.

FAIL Transaction-cost headroom (absolute)

Turnover is 43.6 units a year. The gross mean return falls to zero at a one-way cost of -3.6 bps per unit traded. Base case in this report: 2 bps.

How to test a fix: Measure your real fills (spread, slippage, fees) over a few weeks and re-run with that cost; reduce turnover with wider entry/exit bands and check the Sharpe survives.

FAIL Parameter plateau (absolute)

The chosen variant ranks 25 of 48 (annualised Sharpe -0.13; grid median 0.01; best 0.44). Its one-step grid neighbours average n/a% of its Sharpe; 50% of the grid has a positive Sharpe.

How to test a fix: Prefer the centre of a broad plateau over the single best cell, and report the grid median as the honest expectation.

These are suggestions for further statistical testing, not suggestions to trade. Any change to the rules creates a new variant: count it in N and confirm it on data it was not designed on.

Methods appendix

Sharpe ratio and its standard error

Per-period mean over standard deviation of the audited return series (risk-free rate taken as zero), annualised by the square root of periods per year. The standard error uses the IID-normal formula of Lo (2002) and the non-normal correction of Mertens (2002), which widens the error for negative skew and fat tails. Lo's autocorrelation-adjusted annualisation is reported alongside. [1], [2]

Probabilistic Sharpe ratio (PSR) and minimum track record

The probability that the true Sharpe ratio exceeds a benchmark (here zero), given the sample length, skewness and kurtosis; and the minimum sample length for 95% confidence. [3]

Deflated Sharpe ratio (DSR)

The PSR measured against the Sharpe ratio one would expect from the best of N skill-less trials, where N is the number of variants tried and the dispersion of trial Sharpe ratios is estimated from the variant matrix (or, without one, set to the null sampling variance 1/T). It corrects for selection and non-normality at once. [4]

Probability of backtest overfitting (PBO) via CSCV

The variant matrix is cut into 16 time blocks; for each of the 12,870 ways of picking half of them as in-sample, the in-sample best variant is ranked out of sample. PBO is the share of splits where it falls to or below the median. It assumes blocks long enough to preserve serial dependence and a variant set that represents the real search. [5]

Multiple-testing haircut

The Sharpe ratio is turned into a t-statistic and p-value, the p-value is adjusted for the number of tests (Bonferroni always; Holm and BHY when every variant's returns are supplied), and the adjusted p-value is mapped back to a haircut Sharpe ratio. [6], [7]

White's Reality Check and Hansen's SPA test

Tests whether the best of all variants beats the benchmark in mean return once the search over variants is accounted for. Uses the stationary bootstrap with mean block length T^(1/3) (at least 5) to keep short-range dependence. SPA studentises and recentres, so poor variants do not dilute the power. [8], [9], [10]

Holdout degradation

In-sample versus holdout Sharpe ratio at a fixed split date (by default the last 30% of the sample). The consistency p-value asks how surprising the holdout Sharpe would be if the in-sample Sharpe were the truth. A holdout only counts if it was not used to design the rule. [11]

Period and regime stability

Returns and Sharpe ratio by calendar year and by tercile of the underlying market's trailing 21-day volatility (lagged one day). Descriptive: the tercile cut points use the full sample. [12]

Parameter-sensitivity surface

Sharpe ratio across the supplied parameter grid. The neighbour ratio compares the chosen cell with its one-step neighbours: a plateau (ratio near 1) is less fragile than an isolated peak. [13]

Transaction-cost sensitivity

Net return = gross return minus turnover times a one-way cost per unit traded, over a grid of costs; the break-even cost is where the mean net return reaches zero. Market impact beyond a flat cost is not modelled. [12]

Drawdown distribution by bootstrap

The maximum drawdown is recomputed on 1,000 stationary-bootstrap resamples of the return series, showing how much deeper (or shallower) the worst loss could plausibly have been with the same return distribution in a different order. [10]

References

  1. Lo, A. W. (2002). The Statistics of Sharpe Ratios. Financial Analysts Journal 58(4), 36-52.
  2. Mertens, E. (2002). Comments on Variance of the IID Estimator in Lo (2002). Working paper, University of Basel.
  3. Bailey, D. H. & Lopez de Prado, M. (2012). The Sharpe Ratio Efficient Frontier. Journal of Risk 15(2), 3-44.
  4. Bailey, D. H. & Lopez de Prado, M. (2014). The Deflated Sharpe Ratio: Correcting for Selection Bias, Backtest Overfitting and Non-Normality. Journal of Portfolio Management 40(5), 94-107.
  5. Bailey, D. H., Borwein, J. M., Lopez de Prado, M. & Zhu, Q. J. (2016). The Probability of Backtest Overfitting. Journal of Computational Finance 20(4), 39-69.
  6. Harvey, C. R. & Liu, Y. (2015). Backtesting. Journal of Portfolio Management 42(1), 13-28.
  7. Harvey, C. R., Liu, Y. & Zhu, H. (2016). ... and the Cross-Section of Expected Returns. Review of Financial Studies 29(1), 5-68.
  8. White, H. (2000). A Reality Check for Data Snooping. Econometrica 68(5), 1097-1126.
  9. Hansen, P. R. (2005). A Test for Superior Predictive Ability. Journal of Business & Economic Statistics 23(4), 365-380.
  10. Politis, D. N. & Romano, J. P. (1994). The Stationary Bootstrap. Journal of the American Statistical Association 89(428), 1303-1313.
  11. Bailey, D. H., Borwein, J. M., Lopez de Prado, M. & Zhu, Q. J. (2014). Pseudo-Mathematics and Financial Charlatanism: The Effects of Backtest Overfitting on Out-of-Sample Performance. Notices of the AMS 61(5), 458-471.
  12. Lopez de Prado, M. (2018). Advances in Financial Machine Learning. Wiley.
  13. Pardo, R. (2008). The Evaluation and Optimization of Trading Strategies, 2nd ed. Wiley.

Data and hash appendix

ItemSHA-256 / value
packageholdout-audit 0.3.0
spy_ohlc_daily_yahoo.csvf05d93e20e2ad5f36cf078de7ecabcaa613a3cb8f6a9ddbb2d19f0db44ed3867
audited_series_sha256f193eb82731fd01ffa4daad0de79ef3db64d074fe5836efbf51993b82302bc92
objective_declaration_sha25635b4d77e284614c15fafdacaf91e122b600e520c1ea61e33627a64c3497c765d
preregistration_sha25635b4d77e284614c15fafdacaf91e122b600e520c1ea61e33627a64c3497c765d
config_sha256831792d60c51520d2e2b3e28d92aef6cbdb34510ed73df1ad3514b5f49db792e
bootstrap seed20260925
rubric version1.1 (docs/RUBRIC-v1.1.md)
declared objectivebeat_benchmark
preregistration seal9f25abc24d54753071fc54da00bda52705ea2e7c0b6d2ba3011d7c009fa22d5c (digicert, freetsa; earliest 2026-09-25T18:21:44Z)
objective declaration seal9f25abc24d54753071fc54da00bda52705ea2e7c0b6d2ba3011d7c009fa22d5c (digicert, freetsa; earliest 2026-09-25T18:21:44Z)
rubric document SHA-2562311b126336bab9f426a84f9c9cd9cb937e346b403a62f60e3c96ed8b5868e46
rubric seal record SHA-256ac882c422df5154ec7e6e928904c9099d6b286dc9e5369fece4b85df57044138
rubric sealed by digicert (RFC 3161)2026-09-25T14:20:10Z
rubric sealed by freetsa (RFC 3161)2026-09-25T14:20:11Z

Anyone with the same inputs and package version can re-run the audit and must obtain the same audited-series hash and the same statistics.

Important. This report is a statistical analysis of historical data supplied by or selected for the client. It describes how fragile past results are under standard tests; it says nothing reliable about future results. It is not investment advice, not a recommendation to buy, sell or hold any security or other instrument, and not an offer of any service regulated as investment or trading advice. Past performance, simulated or real, does not guarantee future results. No warranty is given that the data, code or conclusions are free of error. Backtested and simulated results are hypothetical and have inherent limitations.