In project management, performing tasks in parallel, also known as fast-tracking, is a schedule compression technique used to shorten the project schedule without changing the project scope. It involves performing more activities concurrently or overlapping activities that were originally planned to be done in sequence. This approach can help meet time-to-market needs by accelerating the project schedule. However, it may increase project risk and requires careful management.
References: PMBOKGuide - Sixth Edition, Section 6.6.2, "Schedule Compression"