1 / 15

It Seemed Like a Good Idea at the Time…

It Seemed Like a Good Idea at the Time…. Katherine Deibel University of Washington. drizzly. It was a dark and stormy night at the University of Washington… 90 minutes until latest Data Structures project was to be turned in… I was the graduate TA…. My apartment, 10:30pm…

josephine
Download Presentation

It Seemed Like a Good Idea at the Time…

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. It Seemed Like a Good Idea at the Time… Katherine Deibel University of Washington

  2. drizzly It was a dark and stormy night at the University of Washington… 90 minutes until latest Data Structures project was to be turned in… I was the graduate TA…

  3. My apartment, 10:30pm… Nursing the aches of a first year graduate student course load… Undergraduate TA handling the turnin at midnight… I decided to check e-mail one last time before bed…

  4. CHAOS! PANIC! Students could not log in… programs were freezing… I contacted a student by IM… I realized I had to handle this personally…

  5. Undergraduate lab, 11:00pm… All students were panicking … I managed to find a terminal with ‘top’ running… I yelled for my students to terminate their programs… It was too late…

  6. I got to bed about 1:30AM

  7. So What? • An assignment crashed a server… big frickin’ deal right? • But this assignment had been used before with no problems… What was different this time?

  8. The Programming Assignment • Word Frequency Analysis Tool:Implement an unbalanced BST, AVL tree, and a Splay tree where a node <key, value> represents <word, frequency> • Extra Credit:Use gprof to profile your three trees. Run your trees on two inputs: • Any file from Project Gutenberg • The provided file: words.txt a.k.a. The Unix Dictionary

  9. Let’s Do The Math… Unbalanced BST + 45,424 ordered words = BAD (1) (1) + code profiler running = MORE BAD (2) (2)  >6 instances running on the same server = REALLY BAD (3) (3)  all instances running at same priority = SERIOUSLY REALLY AWFULLY BAD

  10. Again… So What? • The lesson is • Use a smaller file next time or • Teach the students to use ‘nice’ • True, but… • This had not been a problem before • Some students successfully profiled their code • Again, what was different? • Something motivated more students to do the extra credit than in previous course offerings

  11. A New [Better] Grading Policy • Joint decision and effort by myself and the undergraduate TA • Both of us graded the assignments • I graded the theory side: • Correctness, • Complexity • Generalizability • Hannah graded the software engineering side: • Programming style • Documentation

  12. Before: Summative assessment Surface grading of code Few grader comments Correctness most important element Style worth 1-2 pts Programs worth 20 pts Perfect scores common Now: Formative assessment Deep grading of code Many grader comments All elements weighed equally Style worth 20+ pts Programs worth 80+ pts More points lost What This Change Meant Students panicked about grades!

  13. The Mystery Solved • We failed to emphasize • Non-perfect scores were expected • Performance would be curved • Students leapt at chance to recover points • More students doing extra credit • More strain on undergraduate servers

  14. Our Mistakes: Redux • Provide too large of an input file • Should have taught students about ‘nice’ • Changed grading policies without addressing underlying student culture about grades and points • Checking my e-mail that one last time before bed

More Related