The false positive I identified in the threat starting post was on in which I was unable to identify on the supposed source webpage any of the words or phrases that was part of the sentence that had been flagged by SafeAssign. Not even a common phrase within the flagged sentence was on the webpage that was identified as the source.
So, for me, a horrible false positive that simply shouldn't occur if the software was worth a darn. Paul Bernhardt Dept of Psychology Frostburg State University pcbernhardt _at_ frostburg _dot_ edu On Mar 23, 2010, at 7:54 PM, [email protected] wrote: > > > Of course, the benefit of using services, such as Turnitin, is that you can > have the student submit the work and the service automatically provides you > with a report of all of the material that it has identified as being > problematic. For those instructors that teach large classes and have a lot of > papers to check, these types of services can save a lot of time and effort > and are, in my opinion, well worth the investment. > > As for false positives, I am not exactly sure how these are being defined in > this discussion, but one issue that I believe is happening increasingly is > that certain sentences that are flagged down as having been copied from other > sources tend to be nothing more than common expressions used by inexperienced > writers or some other sort of match that strongly suggest pure coincidence. > Thus, for example, when I see a Turnitin report that lists several instances > of 'plagiarism', say 20% that amount to separate 1% or 2% snippets each from > a different source, particularly if these are identified as being from > different students from various other universities for a total of 10-12 > different web pages, my sense is that these are likely coincidental matches > (i.e., false positives?). As Ken points out, plagiarism is often done by lazy > students whose MO tends to be the misappropriation of larger chunks of text > from a couple of sources. After all, getting smaller amounts of material from > many different sources is much more work than most lazy students are willing > to do! ;-) > > Ken, I wonder if you would deem it appropriate -and/or if it is not too much > trouble- to share with us how it was that these students were able to fool > the service that your institution was testing. > > Miguel > > > > > Paul Bernhardt wrote: > > > > > > I want to thank folks for their responses to my question. > > > > I was suspecting false negatives might be a problem, too. > > > > If y'all have more to share on plagiarism software in general, I'm happy > > to hear more. I may want to build some ammunition to take to our IT people. > > > > Thanks! > > > > Paul > > > > > I am not a fan of any of the well-known commercial > anti-plagiarism packages because I can generate both false > positives and false negatives easily. > > One semester, I offered extra-credit in a couple of classes to > students who could sneak plagiarised material past a commercial > package and show me how they did it. More than 80% of the > students in the classes could do so and several students showed > me more than 1 way. > > (We were testing the product for adoption. I am amazed that > schools are buying these services without testing. Instead, > schools seem to rely on sales pitches and testimonials.) > > Finally, many cases of plagiarism are done by very lazy students. > Doing Google searches on suspicious phrases often produces the > copied document on the first page of searches. > > Ken > > --------------------------------------------------------------- > Kenneth M. Steele, Ph.D. [email protected] > Professor and Assistant Chairperson > Department of Psychology http://www.psych.appstate.edu > Appalachian State University > Boone, NC 28608 > USA > --------------------------------------------------------------- > > > --- > You are currently subscribed to tips as: [email protected]. > To unsubscribe click here: > http://fsulist.frostburg.edu/u?id=13482.917fac06d4daae681dabfe964ca8c74e&n=T&l=tips&o=1483 > or send a blank email to > leave-1483-13482.917fac06d4daae681dabfe964ca8c...@fsulist.frostburg.edu > > --- > You are currently subscribed to tips as: [email protected]. > To unsubscribe click here: > http://fsulist.frostburg.edu/u?id=13441.4e79e96ebb5671bdb50111f18f263003&n=T&l=tips&o=1487 > (It may be necessary to cut and paste the above URL if the line is broken) > or send a blank email to > leave-1487-13441.4e79e96ebb5671bdb50111f18f263...@fsulist.frostburg.edu --- You are currently subscribed to tips as: [email protected]. To unsubscribe click here: http://fsulist.frostburg.edu/u?id=13090.68da6e6e5325aa33287ff385b70df5d5&n=T&l=tips&o=1496 or send a blank email to leave-1496-13090.68da6e6e5325aa33287ff385b70df...@fsulist.frostburg.edu
