The Origination of all planned work

The Scrum Guide says:

The Sprint Backlog makes visible all the work that the Development Team identifies as necessary to meet the Sprint Goal. To ensure continuous improvement, it includes at least one high priority process improvement identified in the previous Retrospective meeting.

What conclusion would you draw from this about the work a Development Team ought to include in its Sprint Backlog?

I'm going to add to @Ian's very good leading question some additional excerpts from the Scrum Guide. 

First paragraph of the Scrum Guide's section on Product Backlog. (Emphasis added by me)

The Product Backlog is an ordered list of everything that is known to be needed in the product. It is the single source of requirements for any changes to be made to the product. The Product Owner is responsible for the Product Backlog, including its content, availability, and ordering.

Add to that this excerpt from the beginning of the section on Sprint Backlog. (Emphasis added by me)

The Sprint Backlog is the set of Product Backlog items selected for the Sprint, plus a plan for delivering the product Increment and realizing the Sprint Goal. The Sprint Backlog is a forecast by the Development Team about what functionality will be in the next Increment and the work needed to deliver that functionality into a "Done" Increment.

So given those two statements and the one that @Ian provided go back to @Ian's question. 

Apologies to Ian and Daniel, but in reading the question, this is the section of the Scrum Guide that immediately popped into mind:

The Development Team modifies the Sprint Backlog throughout the Sprint, and the Sprint Backlog emerges during the Sprint. This emergence occurs as the Development Team works through the plan and learns more about the work needed to achieve the Sprint Goal.   As new work is required, the Development Team adds it to the Sprint Backlog... Only the Development Team can change its Sprint Backlog during a Sprint. 

Therefore, what is the answer to the question "Does all planned work done by the Dev Team originate from the Product Backlog?"? 

Hi Timothy, 

Can a process improvement identified in the previous Sprint Retrospective cause work for the Development Team? If so, where would this work be made transparent? 

What opportunities exist to inspect and adapt? What are the Development Team expected to achieve, and who is able to inspect that, and potentially hold the team accountable?

When would it be appropriate to inspect the "work done", and could there be more valuable things to inspect instead, if Scrum is followed by the organization?

@Timothy

I see your point and it is valid.  I did miss that part.  I completely agree that new work identified in the process of doing the work can be added to the Sprint Backlog.  However, the part of the original question I have emphasized below drove my answer. 

What do you think? Must all planned work done by the Dev Team originate from the Product Backlog? 

I do believe that all work should originate from the Product Backlog.  Any additional work uncovered during the Sprint did originate from work that came from the Product Backlog. I do not think that new work that comes from outside sources should be created directly into the Sprint Backlog.  That work should be added to the Product Backlog first so that it can be ordered among the existing work.  If the Development Team should choose to add that work to the Sprint without endangering the Sprint Goal, that is their decision and does not contradict the Scrum principles. 

@ Johannes,

Can a process improvement identified in the previous Sprint Retrospective cause work for the Development Team? If so, where would this work be made transparent? 

In my opinion, the Scrum Guide is fairly explicit on this topic:

The Sprint Backlog makes visible all the work that the Development Team identifies as necessary to meet the Sprint Goal. To ensure continuous improvement, it includes at least one high priority process improvement identified in the previous Retrospective meeting.

It seems the logical conclusion is that such a process improvement would be made transparent through its presence in the Sprint Backlog.   And to Dan's comment, since the Sprint Backlog is but an extension of the Product Backlog, it would seem that any improvement items need to first be created in the Product Backlog.

Hi everyone,

so the correct answer is Product Backlog or Sprint Backlog?  I am confused now. I was really thinking some additional work will emerge at the sprint backlog but I dont know now the answer to the trickie question now if the origin of all DT work is the Product Backlog.

Hi everyone, in my opinion, answer to the question ''Must all planned work done by the Dev Team originate from the Product Backlog?''  is NO, or FALSE.  Here is the answer why I think so.

As it is said in the scrum guide :  ''Product Backlog is the single source of work undertaken by the Scrum Team. Product Backlog items that can be Done by the Scrum Team within one Sprint are deemed ready for selection in a Sprint Planning event."

Moreover, it says in the scrum guide that ''The Sprint Backlog is composed of the Sprint Goal (why), the set of Product Backlog items selected for the Sprint (what), as well as an actionable plan for delivering the Increment (how). Consequently, the Sprint Backlog is updated throughout the Sprint as more is learned. Until this part,  we can say that the answer should be YES,  Product Backlog.

However, in the scrum guide it also underlines about the Sprint Retrospective that ''The Scrum Team identifies the most helpful changes to improve its effectiveness. The most impactful improvements are addressed as soon as possible. They may even be added to the Sprint Backlog for the next Sprint." From this sentence, I conclude that some work to be done by the development team regarding the improvements may originate from the Sprint Retrospective. so the answer should be NO for the question here above.