Remove the Survivorship Bias from the back tests database. If those stocks that were removed from the database due to delisting, bankruptcy, bought out, etc. and NO LONGER trade, are removed from the database, it skews the evaluation creating a favorable, but inaccurate, performance of the strategy being tested. This does not represent a true model of actual performance and creates a chain reaction that can result in a disappointing outcome.
Remove the Survivorship Bias from the back tests database. If those stocks that were removed from the database due to delisting, bankruptcy, bought out, etc. and NO LONGER trade, are removed from the database, it skews the evaluation creating a favorable, but inaccurate, performance of the strategy being tested. This does not represent a true model of actual performance and creates a chain reaction that can result in a disappointing outcome.