Challenges of scaling agile principles and practices
Development teams typically refine their backlog up to two to three iterations ahead, but in larger organizations the product marketing team needs to plan further ahead for their commitments to market and discussions with customers. They will often work with a very high level, 12–18-month roadmap, then plan collaboratively with the teams for three months of work. The development teams will still get into detailed refinement 2-3 iterations ahead, only getting into detailed task plans for the next iteration
Keeping agile at abstract levels of responsibility
While development teams have a number of frameworks that define how they should be agile, there is very little that describes this for management. SAFe delivers many of the same principles, such as cross-functional teams, to the groups that handle the more abstract levels of responsibility and planning (product and portfolio). SAFe has also been criticized for aggregating too many disparate practices.
Dealing with delegated authority
In Scrum, the product owner is expected to assume responsibility for the full product life-cycle, including the return on investment of development decisions, as well as performance in market. On large-scale developments, the organization needs a view across multiple team backlogs, such as provided by a product manager. Although SAFe assumes the product owner role sits with product management, it has nonetheless been criticized for separating product owners into the development organization.
Synchronizing deliverables
Agile frameworks are designed to enable the development team to be autonomous and free to design how they work. SAFe acknowledges that, at the scale of many tens or hundreds of development teams, it becomes increasingly chaotic for teams to fully self-organize. It therefore puts some constraints on this, so that where teams are working on the same product, their deliverables can be better synchronized for releasing together, although this has been one area that SAFe has been criticized.
Allowing time for innovation and planning
The SAFe planning cycle recommends including an additional iteration after a release, so that teams can improve their practices and are ready for the next planning increment. Earlier editions of SAFe also designed this to be a hardening iteration, that is to stabilize or harden the product before releasing it. This was predicated on the complications of working with large integration environments where dependencies meant that you could not test everything until the very end. SAFe was criticized for this as it represented an anti-agile or waterfall element. This is not included in recent editions of SAFe.
Source: Wikipedia!