When faced with a tight deadline and the need to comply with new laws, the project manager should first review organizational process assets (OPAs) and perform analogous estimating. This is because OPAs can provide valuable historical information on how similar projects were executed, which can inform the current project's planning and execution. Analogous estimating, in particular, uses data from previous, similar projects to estimate project duration and cost. Given that a similar project was completed recently, this information can be used to make more accurate predictions for the current project. This approach is recommended by the PMBOKGuide as a valid method of estimation when there is limited information available and time is of the essence123.
References: The recommendation to review OPAs and perform analogous estimating is supported by the PMBOKGuide and the principles of project estimation as outlined in PMI's resources12345. Additionally, the importance of leveraging historical data for project estimation is emphasized in the Professional in Business Analysis reference materials678910.