Scrum Burndown Patterns [closed]

Question

I'm in a 10 person team working on a large legacy code base with a less than ideal product owner. Our backlog is in pretty bad shape and large epics have frequently been breaking our sprints. The team also struggles with its definition of done - some members write unit test religiously, others don't, sometimes depending on time available.

So, I've been seeing some interesting burndown patterns, and I'm wondering which patterns others are seeing and what they mean.

Pattern 1:

#
# # 
# # #  
# # # #     
# # # # #   
# # # # # #
# # # # # # #

• Positive explanation: "All good."
• Negative explanation: "Too good to be true. What's really going on?"

Pattern 2:

#
#
# #
# #     
# # #   # 
# # #   # #
# # # # # # #

• Positive explanation: "This was way easier than we thought, let's pull in more stories."
• Negative explanation: ??

Pattern 3:

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# # # #
# # # #  
# # # #     
# # # # #   
# # # # # #
# # # # # # #

• Positive explanation: "Not sure about this work at first, then turns out easier than we thought."
• Negative explanation: "Not enough progress, let's stop writing unit tests to get 'done' on time."

Answer 1

This is recognized around our office as the "Ah, crap! I forgot about that." burndown:

    # # #
    # # # #
    # # # # #
    # # # # # #
#   # # # # # #
# # # # # # # #
# # # # # # # #

Answer 2

Pattern 2 on the negative side is "didn't estimate too well".

Here are some burndown charts I've used. Ignore the background pictures - they are there just to entertain the people I work with and have nothing to do with our work otherwise. alt text http://www.atalasoft.com/cs/photos/techtalkgallery/images/16157/425x285.aspx

I love this chart. It's very typical of a good chart we start a little slowly as we shed other tasks, bear down into the work, get interrupted by other things and push to finish.

alt text http://www.atalasoft.com/cs/photos/techtalkgallery/images/16155/425x262.aspx

In this chart we started very steadily and then took off actually finished ahead of time.

alt text http://www.atalasoft.com/cs/photos/techtalkgallery/images/16156/425x264.aspx

In this chart you can see that we started very typically and then a task that looked easy turned out to be heinously hard. I think we ended up halting this sprint and building a new one.