Increment description appears to be factorial
In the Statement "The Increment is the sum of all the Product Backlog items completed during a Sprint and the value of the increments of all previous Sprints"
do the words "and the value" indicate addition ?
If so, since the increments of the previous Sprints also contain the sums of all previous Sprints, one ends up with a factorial function.
My old fashioned Dictionary (goggle) describes an increment as just the additional part, i.e. here the sum of all Product Backlog items completed during a Sprint.
"an increase or addition, especially one of a series on a fixed scale"
Even if I Interpret the Statement to be the work done in a sprint plus the previously done work, that seems like a Grand Total, not an increment.
Please note, I am not thinking of Software but of say a Widget factory. If only 8 items are produced in a sprint then the customer should only be invoiced for the 8 items and not 8 plus the sum of all previously delivered items.
When I read that phrase, my understanding is that the intention is to indicate that the value does not decrease because of the work done. The output of every Sprint is a potentially releasable Product Increment. Every Increment has all of the Product Backlog Items that achieved Done in the current Sprint, plus all Product Backlog Items done in every previous Sprint. The value of a given Increment is not going to be less than the value of a previous Increment - that is, if the potentially releasable Product Increment were to be released by the Product Owner, the value would be as much as the previous released Product Increment, if not more.
I read it as the increment of Sprint 5 includes the increments from Sprint 1-4 because you are incrementally delivering value. Each Sprint delivers a potentially releasable increment and at some point the decision is made to release it. So you would include all Sprint increments since the last release.
For a better way to envision it think of this example. The goal is to release a product that allows users to have a task list online. First Sprint you release a user interface that shows a list of things (typically a list of stuff created by manually inserting rows into a database.) This allows you to get feedback on the user interface layout. Second Sprint provides the ability to add an item. Third Sprint adds the ability to update an item. The ability to delete items comes in the Fourth Sprint. Ability to mark items as "in process" or "completed" comes in Fifth Sprint. Now we have something that has enough functionality to release. Each sprint builds upon the previous sprint.
Now whether you want to use mathmatical terms to explain that or not is up to you. I just see it as incremental delivery of the solution to a problem.
If an increment did not incorporate the value of prior increments, the work to realize the missing value would have to be accounted for again on the Product Backlog.
Hello , thanks for your answers. I think my misunderstanding is the scrum specific meaning of the word increment.
For example in pseudo Code :
(Lay People) : Total = Total + Increment
(Scrum) : Increment = Increment + WorkFinishedInSprint
Increment = Product + WorkFinishedInSprint
Product = Release(Increment)