Check positions before performance
Start with current broker quantity by security. If the ledger quantity differs, do not review returns yet. The performance screen is downstream of the ledger.
Sort mismatches by largest market value first. A small fractional difference in a large holding often matters more than a full-share mistake in a tiny position.
Check for possible duplicates
Duplicates often share the same date, security, quantity, and price. They can also appear when one row uses a ticker and another row uses the company name.
Keep original broker text available while resolving names. That makes it possible to see whether two rows are truly the same transaction or two separate fills.
Check for missing entries
Missing rows often show up as cash that does not reconcile, dividends with no matching cash movement, or a position that appears without a buy.
Use Portle to inspect these cases, then correct the source ledger. A current-looking dashboard is not useful if the underlying record is incomplete.