Wednesday, September 14, 2022

To Stop Cheating In College Physics Examinations Departments Need To Ban Virtual Testing

Physics & astronomy prof uses problem solving in class to deter cheating
                   Segment of cheating 'chat' during one physics take home exam captured in PT piece

The educational system will break down if cheating is widespread. I regard it as a public health problem rather than a crime.”Anonymous Physics professor quoted in Physics Today article.

The Physics Today article, 'College Physics Instructors Adapt TheirTeaching To Prevent Cheating' (August, p. 25) was mind blowing.  We learned, for example, that cheating - especially on class tests, homework has become as endemic as the pandemic since the lockdowns. Indeed, math and physics college instructors across the U.S. and beyond are grappling with how to deter cheating and reassessing how they assess their students.

Who or what are the primary culprits in this new cheating venue?  Most of the profs cited in the PT piece appeared to blame a website called 'Chegg'. Why Chegg?  Well, as we learned "Chegg offers libraries of searchable solutions and the option to post new problems with requests for solutions"  . Other companies provide similar services to Chegg, e.g.:   Quizlet, Bartleby, and Course Hero. Quizlet profits through advertising only while the others charge monthly fees ranging from $9.95 to $39.99.

How bad can it get?  According to one account of the experience of math and physics grad (Samantha Kelly)  from UC- Berkeley:

"After she finished an online midterm exam for a junior-level quantum mechanics class in summer 2020, she 'poked around online and found it had been uploaded to Chegg' while the exam was still in progress. She has also seen group chats online where students discussed how they would work together on an upcoming exam."

This is bare bonkers nuts, of course. An upper level QM exam uploaded to Chegg while the exam was in progress?  She then added the most cogent part herself about how this cheating affects the Gaussian distribution:

"The distributions of grades on exams have started to reflect cheating—whether by Chegg, group chats, or other means. Instead of a nice Gaussian distribution, you see a normal curve but with a smaller peak, plus a significant peak at the 95 to 100 mark.”

Then there is Mark Messier, neutrino physicist at Indiana University -Bloomington, who was grading exams for his introductory mechanics course when he suddenly became suspicious.  Let's back up here to show a bit of what such a course would consist of, based on a few of my earlier posts concerning Lagrangian and Hamiltonian dynamics, e.g.



x1 =   L1  sin f1

x1’ = L1  cos  f1  f1

y1 =   L1  cos f1

y1’ = - L1  sin  f1 f1

V =  mgL1 (1 -   cos  f1)

T1  =  ½  m( r q’ 2 )  =    ½  m1( L1  f1’ 2 )  and   T2 =   ½  m2( x2’ 2   + y2’ 2)


x2 =   L1  sin f1  +   L2  sin f2

y2 =   L1  cos f1  +   L2  cos f2

x2’   = L1  cos  f1  f1’    + L2 cos  f2  f2’   

y2’   = L1  sin  f1  f1’    -   L2 sin  f2  f2’   


T2  =    ½  m2(L1 2   cos 2   f1  f1 2   + L2 cos 2  f2  f2’    +

 2L1 cos  f1  f1’  L2 cos  f2  f2’    +  L1 2   sin 2    f1  f1 2   +

  L2 sin 2  f2  f2’   + 2L1 L2 sin  f1 sin  f2 f1’ f2’ )

T2 =   ½  m2(L1 2  f1 2   +  L2 2  f2 2   + 2L1 L2 cos (  f2  - f1)  f1’ f2


L =  ½  m1 L1 2   f1 2    +  ½  m2( L1 2   f1 2   +  L2 2  f2 2  

+ m2 L1 L2 cos (  f2  - f1)  f1’ f2’ – m1 g L1 (1 -  cos  f1  )  -

m2 g [L1 (1 -  cos  f1 )  +   L2 ((1 -  cos  f2 ) 

Fairly straightforward if one knows his/her way around obtaining the Lagrangian from a simple mechanical system.  But as Prof. Messier realized:

“I saw idiosyncratic features repeated in the solutions that multiple students turned in.  Things like use of odd variables."  Then a quick Google search turned up five of the six problems from the take-home exam on Chegg. 

"And I could see they were scanned versions of my exam problems."

One commonality in all these episodes appears to be that:
"Students largely lost access to easy group interactions and group study situation. Instructors say students have become more hesitant to come in for help. That got lost in the pandemic, and companies like Chegg jumped in.

According to another math prof, Juan Gutiérrez. he witnessed:

  "Answers being posted on Chegg within five minutes of a test going live.”

Well, just ban online exams, right?  But we're informed: 

"Even with the return to in-person classes, many instructors continue to offer a choice of taking exams in person or virtually. 'Students pick the environment most suited to their success, says Jonathan Perry, a physics instructor at UT Austin. Some students may feel more comfortable at home listening to music, "

Added another instructor:

"COVID is still a thing. This past spring, about a quarter of my students chose to take their finals asynchronously from home."

Wow! If only we could have done that during the Cuban Missile Crisis in 1962. It really would have helped the nerves!  But seriously, if a kid has been properly vaccinated this ought not be an issue and there is no excuse for granting special exceptions.  Those put the in-class exam students at a decided disadvantage given they can't just Google a problem solution.  Oh wait! 'Our kids are on an honor system and we believe them!'  Then you're a pack of idiots

Prof. Gutierrez notes: "Companies like Chegg disproportionately attract students who enter college with less preparation—often from less affluent school districts, which tend to produce more Hispanic and African American students. “Every city has sections that are under-resourced, and often students from those areas have a harder time and feel more pressure to turn to companies like Chegg.”

This is unfortunate, but again, colleges then need to demand higher entry standards or put these disadvantaged students into lower, remedial classes before doing the full throttle courses.  This was always done, for example, back in the 60s, and no questions asked.  A kid deficient in math? Ok, then he took basic math intrduction instead of Unified Algebra and Trig or first year Calc.

To stop cheating, which only contributes to grade inflation - see ink below- we need to halt special "asynchronous" testing done virtually. Yes, take home tests can still be given but design them so students can't simply upload solutions from Chegg or similar sites.  One way is to design test problems with an emphasis on inquiry as well as knowledge.  

One example: 

 a)A group of 4 astronauts lands on Mars with solar radiation collection material of total area 2000 m 2. If the efficiency of the material is 30%, and the ambient night time temperature on Mars (for their base location at Isidis Planitia) is -40 C (10C day time), will they have adequate collecting material if the solar constant on Mars is 620 W/ m 2 ? (Assume insulating material with a thermal conductivity of 0.08 W/mC, and a need to keep the inside area of their domecile at least at 10 C, requiring solar radiant energy collected of at least 1,200 W per minute for an area of 10 m x 10 m.)

c) Estimate the thickness of insulating material they're likely to need in order to make it work. Comment on whether this expedition is even feasible given the limits of their materials, and that no more than 100 m3 of insulating material can be taken.

I suspect analogous inquiry problems in classical mechanics, quantum mechanics, or thermodynamics problems can also be prepared if an instructor is creative enough.  What we can't keep doing is making excuses for less able or disadvantaged students to cheat and upset the distribution for everyone.  It isn't fair and certainly isn't American. 

Short of that, I don't see how physics (or math) cheating can be stopped anytime soon. But banning virtual (out of class) exams, tests, would be a superb start - if departments have the will to do so.

See Also:

Grade Inflation Continues to Render Most College Scholastic Honors, Achievement Meaningless

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