Keep every cost in its own row

Record the evidence and unit behind each input before comparing a backtest. A fee, reference-to-fill price difference and funding settlement have different bases and timing.

LineRecordCommon audit question
FeesEach fill, executed notional, rate, account tier and source dateDid you include both sides at the contract's fee basis?
SpreadReference price, bid/ask and timestampIs the same spread already included in the fill price?
SlippageModeled fill versus reference, with order assumptionsIs this additional adverse movement or duplicated spread?
FundingEligible settlement time, rate unit, sign and price basisWas the position open under the venue's rule at settlement?

Compare whole-run scenarios

  1. Freeze the strategy, dataset, instrument and measurement convention.
  2. Enter sourced baseline assumptions and disclose what remains unknown.
  3. Set a higher-cost case before reviewing the outcome.
  4. Replay the complete strategy and compare net result, drawdown, trades and exposure.

The download includes fill and settlement ledgers, a scenario grid, reconciliation table and review checklist. It contains no preset fee or funding rates.