Why does SAFe have different definitions for terminology otherwise used in Agile/Scrum
I am trying to understand why SAFe (Scaled Agile Framework) has differing explanations for commonly used Agile terminologies. For ex: Estimating using story points (while relative even in SAFe) is defined/described with prescriptions as opposed to the traditional way where points are treated arbitarily. In SAFe however, all teams apparently have a common understanding of this concept.
Read Starting Baseline for Estimation in https://www.scaledagileframework.com/story/
Similarly, the concept of Spikes; I read that Spikes have to be both estimated and sized instead of just being timeboxed. How does estimating and sizing Spikes help in SAFe?
I had a rather embarassing experience when I realized late how these concepts were differently understood and used in SAFe. What do others think based on their knowledge and experience of SAFe? Do those that strictly teach Scrum make these variations explicitly aware ?
OK, Scrum and SAFe are agile "way of working" so to say, but that does not mean they are referencing the same concepts in the same way. In my personal opinion, since Scrum is so widely used and known, the boundaries of what is "Scrum" and what is "Agile" have become and are becoming more vague each day (and I do not mean this in a bad way).
Also, in my eyes, SAFe is not a framework like Scrum, in the sense that SAFe is much more descriptive, predicting, prescribing and detailed in how things should be done, where Scrum is much more like a real framework and leaving it up to you to implement the concepts. So, in my opinion, Scrum is a much more high-level open-minded approach, where SAFe could be "just one of the ways" to implement Scrum, adding a lot of artifacts, events etc. to what Scrum itself is using.
Also, SAFe is more focussed on scaling agile, not necessarily on team level. So you should compare SAFe more to Nexus, where the same statements as above apply.
My experience with SAFe is that on the scaling part (multiple teams, product phases across organization levels) gives very good tools to handle scaling and levels, and can be very effectively put into use for the scaling part, where on Scrum team level, we still do Scrum, with some additions like PI planning events.
So, in my personal opinion, it is no problem at all, as long as everyone is on the same page
Before I start I want to point out that anything I say below is my opinion, only my opinion and in no way reflects the beliefs of scrum.org or any of the contributors to this forum. Others may share my opinion or completely disagree. I appreciate that and have been known to modify my viewpoint based on other's views.
I agree with everything @Xander said. Scrum and SAFe are two entirely different things. Just as Nexus is somewhat different than Scrum, when attempting to scale there are things that have to be modified. You pointed out inconsistencies between the two but the same can apply to SAFe and Kanban or SAFe and XP.
SAFe uses many of the familiar agile terms but they are modified to fit into the "framework" that they prescribe. I really feel that the framework of SAFe is more a prescribed process. They say that you can modify their process to work for your company and that is about all that I can see to justify the framework statement. But when you reach the point of scaling across many teams, many products, many job functions, etc, there is work and interactions that need to modify to accommodate the successful integration of those components. Any scaling method you find will include the "changes" needed. SAFe, Nexus, LeSS all introduce modifications. And not one of them is the "right way".
It is suggested that you use one of their certified coaches or a certified partner in building your implementation for many scaled agile frameworks. These seem to be much more commercialized than others that are provided without those needs. I have noticed more and more companies using SAFe in my area. Many job postings are now asking for SAFe experience. While it might be a more prescribed and heavier method, it is also very popular. Is that a bad thing? No one can say except the companies that are doing it.