A quality control (QC) engine analyzes sample code provided by a user and then generates example code that more effectively performs the same or similar operations performed by the sample code. An objective model analyzes the sample code to generate one or more tags indicating the intended objective(s) of the sample code. The quality model analyzes the sample code to generate one or more ratings indicating the degree to which the sample code achieves each intended objective. The performance model analyzes the tags and the ratings and estimates the performance of the sample code when executed in a production environment. The recommendation engine queries a database of code based on the tags, the ratings, and the estimated performance of the sample code to determine example code that achieves the same or similar objectives(s) as the sample code, but with at least one of higher ratings and greater performance.