OPM3 (Organisational Project Management Maturity Model) standard has been developed by The Project Management Institute to help organizations assess the maturity of their PM practices and then chart a path to improve the PM aspects in their organisation. It provides a comprehensive approach helping organizations to assess and develop their ability to deliver projects successfully, consistently and predictably.
OPM3 offers three interlocking elements:

• KNOWLEDGE element
• ASSESSMENT element
• IMPROVEMENT element

The KNOWLEDGE element found in the OPM3 Knowledge Foundation book, lets organizations uncover hundreds of Best Practices and shows them how to use them. The ASSESSMENT element is an interactive database tool available on the web site that organizations can use to evaluate their current situation and identify their areas of improvement. And the IMPROVEMENT element helps organisations map out the steps needed to achieve their goals.
The OPM3 Standard incorporates the PMBOK Guide, The Standard for Program Management and The Standard for Portfolio Management into one framework for assessing capabilities and producing specific outcomes. OPM3 has two automated tools: OPM3 Online and OPM3 ProductSuite. 

OPM3, addresses the project management domain, the program management domain, the portfolio management domain--either one, two or all three domains, or any combination of these what suits the needs and capacity of the user. The OPM3 Standard has 488 best practices (BPs) and 412 out of them pertain to the Standardization, Measurement, Control and Continuous Improvement of the Project, Program and Portfolio Management Processes. These 412 best practices organize 1,530 Capability-Outcome Statements. This is because each of the OPM processes requires 15 Capability-Outcomes. The project management domain has 42 processes, the Program Management domain has 47 processes and the Portfolio Management domain has 13 processes--summing to 1,530 Capability-Outcome statements.

Organisations need a tool that helps them to determine if they are ready to assess and improve themselves. According to John Schlichter, the CEO of OPM Experts LLC and an expert on the subject feels that OPM3 ProductSuite is far better that OPM3 Online.