A useful slippage journal records the market reference, your order and the actual fill separately. That lets you investigate execution costs without blaming every difference on “slippage.”
Why a fill price is not the whole cost
Execution cost has more than one part. CFA Institute distinguishes explicit costs, such as commissions and fees, from implicit costs that can include spread, market impact, delay and unfilled trades. The SEC’s investor guide also describes how order routing and price can affect the transaction. These sources discuss securities markets, so treat the categories as a measuring framework—not a ready-made CFD cost formula. See the CFA Institute trading-cost overview and the SEC’s order-execution guide.
A displayed quote is a snapshot, not a promise that your order will fill there. The SEC’s guide says stock prices can change while an order is routed and price improvement is an opportunity rather than a guarantee; CFA Institute also includes delay and unfilled trades among implicit trading costs. Neither source establishes how your broker handles a CFD order. The instrument and venue matter.
The fields that make a trade reviewable
Capture these fields before the details blur together. Use your platform’s timestamps and save the quote or order-history record when available.
| Record | What it helps separate |
|---|---|
| Symbol, direction, order type and size | Unlike instruments and order instructions are not treated as one sample. |
| Decision time and order-submission time, with timezone | A delayed decision or transmission is distinguishable from the fill itself. |
| Bid and ask you observed when the decision was made | The quoted spread can be calculated from that snapshot, if the quote is reliable. |
| Intended entry and the reason for that reference | “Expected price” needs a defined benchmark, not a number chosen after the fill. |
| Fill time, fill price and filled quantity | Partial fills and price movement remain visible instead of collapsing into one average. |
| Commission, swap and other charged costs | Explicit charges stay separate from price differences. |
| Session, volatility/event note and platform or connection issue | These are comparison labels, not proof that a condition caused a worse fill. |
| Screenshot or export reference | Another person—or future you—can check the original record. |
CFA Institute’s transaction-cost framework includes direct costs and less visible costs such as spread and delay. Its implementation-shortfall discussion also counts missed or unfilled opportunities. In a historical review, the FCA reported that investment managers sometimes used execution-cost data inconsistently or as a tick-box exercise. The SEC describes a broker’s duty to assess periodically which markets offer favourable execution terms. The useful lesson for a personal log is modest: review the records and note what you learned; collecting rows alone does not explain them. Read the FCA’s historical review and the SEC guide. Those sources concern investment managers and stock orders, not a retail-cTrader standard.
Compare the same kind of execution
Group records by symbol, order type, direction, size band and session before comparing them. Keep market and limit orders apart. Mark partial fills and rejected orders instead of dropping them; otherwise the cleanest-looking fills may be the only ones left in your sample.
For each order, define the reference price before looking at the outcome. A market buy can be compared with the ask you observed at submission; a market sell with the bid. If your platform does not preserve that quote, record that the benchmark is missing rather than reconstructing it from a later chart candle. This is a workflow convention, not a universal best-execution test.
A hypothetical review
Suppose a demo market order fills at a different price from the quote you wrote down. Your log shows that the difference coincided with a partial fill and a connection interruption. That is a lead to inspect—not evidence that the interruption caused the difference, and not a verdict on the broker. Repeat the review across comparable orders and keep the original records.
The FCA’s review concerns investment managers, while the SEC guide describes stock orders. Neither sets a retail-cTrader standard. Their scopes are why the log should describe what you observed on your own account, not claim regulatory compliance or rank providers.
Turn the log into a careful comparison
A useful review asks a narrow question: do like-for-like orders show a repeatable difference worth investigating? The FCA describes monitoring that examines execution costs and trends; the CFA Institute material explains why one benchmark may omit parts of total cost. The SEC’s description of periodic execution review is another reminder that looking at evidence matters more than merely collecting it. None guarantees that a small personal sample can identify a cause.
Start with a compact table or spreadsheet. Keep the raw records unchanged, add a separate analysis column, and write down exclusions. If you change the reference price, session labels or order grouping, preserve the old version so the comparison can be reproduced.
For simulated costs, see how to test slippage in a cTrader backtest. For the broader record-keeping side, audit a cBot decision log. realbacktesting is a trading-software studio for cTrader; its proof page explains how to check published backtest reports and reproduce their conditions in your own platform.
What your journal can—and cannot—show
A personal execution journal can make your own fills easier to review and can reveal which questions deserve a closer look. It cannot, by itself, prove best execution, establish a broker-wide pattern or show that one session caused a result. The quality of the conclusion cannot exceed the quality of the timestamped records.
Keep the raw evidence. The explanation can wait until the comparison is fair.