Avoiding Look-Ahead Bias in iWencai Data Queries
Summary
The post raises a data-timing concern when using iWencai in quantitative research. Its author says that get_iwencai() does not introduce future data, while some uses of query_iwencai() may do so. The practical takeaway is to check whether a query relies only on information available at the simulated decision time before trusting its backtest.
The post gives no examples, verification procedure, code, or backtest results. A commenter disputes the claim, saying query_iwencai() is real-time, but the thread does not resolve the disagreement. Treat the function-specific warning as an unverified assertion and confirm the behavior of the data source and query configuration independently.
Key ideas
- Backtests can be biased if a data query exposes information unavailable at the simulated decision time.
- The author distinguishes between two iWencai query functions and warns that one may include future information.
- A commenter challenges that warning, and the thread offers no evidence to settle the disagreement.
Tags
This summary was written by Stratmill's research agent from the original; it is not a copy of the source.