OUT-OF-SAMPLE QUANTITATIVE RESEARCH

Test hypotheses
beyond the
sample.

Ziju Quant studies signals that could be traded. A hypothesis has to be stated, then tested on data that was not used to build it, after costs, and against rules that would retire it. One backtest is not a conclusion.

RESEARCH FRAMEWORKResearch validation path
Illustrative · Not live data
  1. HypothesisState the question
  2. PerturbPerturb inputs
  3. Out-of-sampleHold out data
  4. ReviewReview the record
RESEARCH MODEMultiple tests
RISK LAYERInvalidation first
REVIEW STATEOpen to reversal
Conceptual research framework: state a hypothesis, perturb it, test it out of sample, then review it. It does not represent investment performance.

Research topics: FACTOR RESEARCH, ROBUSTNESS, RISK BUDGET, PORTFOLIO CONSTRUCTION, EXECUTION RESEARCH, MODEL REVIEW

ON BOOTSTRAP

One backtest is not a conclusion.
We examine where signals may fail.

Here, bootstrap is a research metaphor. Resampling can help assess estimation uncertainty, but it cannot replace a time-ordered out-of-sample test. Candidate signals also need a separate check for costs and invalidation rules.

Fitting history is not enough. The evidence that would retire a signal has to be written down first. Parameters are not retuned to suit a result. Signals held together are checked for the same underlying risk.

FOUR RESEARCH AREAS

State the question before managing the risk.

01

Factor research

FACTOR RESEARCH

Start from an economic mechanism, then test whether the signal is robust, explainable, and still worth trading after costs.

Economic logicOut-of-sampleRobustness
02

Portfolio design

PORTFOLIO DESIGN

Check whether the signals share the same risk, then set weights under correlation and risk-budget constraints.

CorrelationRisk budgetConstraints
03

Execution research

EXECUTION RESEARCH

Costs, capacity, and liquidity are included before anyone treats a frictionless backtest as a result.

Trading costsCapacityLiquidity
04

Risk framework

RISK FRAMEWORK

Data, models, the portfolio, and execution each have monitors. The action after a breach is written down in advance.

ScenariosExposure limitsResponse

A RECORD FOR EVERY CHANGE

Each change
needs a record.

Hypothesis, out-of-sample testing, portfolio construction, and review are fixed steps. The discussion follows the record, not a single equity curve.

01

Frame a hypothesis

The question has to be falsifiable, and it has to come from market structure or behavioral bias.

02

Test out of sample

Hold out time-ordered data that was not used in development, then check whether the result remains under rolling windows and stress scenarios.

03

Set portfolio weights

Control correlation and shared exposure so several signals are not just the same risk counted again.

04

Review continuously

Record drift, structural change, decay, and invalidation rules when they appear, not after the fact.

SIX QUESTIONS BEFORE A CONCLUSION

Before the conclusion,
answer six questions.

We do not look only for evidence that supports a conclusion. Disconfirming evidence, the boundary of use, and the exit rule are written down before the conclusion.

01MECHANISM

Logic

Why might the signal exist? Could returns reflect risk premia, behavioral bias, or market constraints?

REVIEW FOCUSFalsifiable premise
02DATA INTEGRITY

Data

Can data versions, true availability times, and missing-value treatment be reproduced independently?

REVIEW FOCUSPoint-in-time integrity
03ROBUSTNESS

Validation

Does the result survive out-of-sample, rolling-window, parameter, and alternative-sample tests?

REVIEW FOCUSCross-sample stability
04IMPLEMENTATION

Trading

After costs, slippage, market impact, and capacity constraints, does the premise still hold?

REVIEW FOCUSTradability assumptions
05EXPOSURE

Risk

Which exposures drive returns, and what happens under stress and extreme scenarios?

REVIEW FOCUSBounded exposure
06INVALIDATION

Invalidation

Which observable evidence triggers a lower weight, renewed validation, or retirement?

REVIEW FOCUSExplicit exit rules

LIMITS, THEN A RESPONSE

Risk needs measurement,
and clear response rules.

Data quality, model stability, portfolio exposure, liquidity, and execution drift each need a boundary and a pre-written action for when that boundary is crossed.

Diversify return sourcesInspect tail exposureDetect model driftPreserve liquidity headroom
RISK REVIEW LAYERSILLUSTRATIVE FRAMEWORK · 04 LAYERS
  1. 01DataPoint-in-time integrity
  2. 02ModelCross-sample stability
  3. 03PortfolioBounded exposure
  4. 04ExecutionTradability assumptions
Illustrative · Not a rating
Conceptual view of four risk-review layers: data, models, portfolio, and execution. It is not a rating of a real portfolio.

LATEST NOTES

Research notes

Notes and discussions about research method.

View all research notes
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