Discrepancy in Numbers

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nu2004

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I just wanted to make a point that I think is often missed around here, particularly with how worked up people get about numbers.

If anyone has taken a look at the recent MSAR (2009 ed), try to pop your eyes back into your head. I know that I was certainly shocked to see how much numbers have gone up in only the last few years (I have the 2007 MSAR). It seems like just about every school now has average GPAs around the 3.8 mark and MCATs that are 33-35. How is this possible, you might ask?

I haven't read the technical information in the MSAR regarding how they collect data (I'm not sure they give an exhaustive methodology anyway), but a quick comparison to the US News numbers shows a pretty significant discrepancy between median GPAs and MCAT scores vis-a-vis the MSAR.

What I suspect is happening is that the MSAR is reporting median statistics for all accepted students rather than just matriculants. This has the effect of inflating numbers because a school can honestly say "the median GPA for accepted students was 3.8" even if the median GPA for people who actually chose to go there was 3.6. Here's an example of how this would work:

Susie graduates from Cal Tech with a 4.0 and is disappointed with her 43 MCAT. She applies early and broadly to 20 schools, and returns secondaries for all 20.

Dave wakes up one day in a cloud of marijuana smoke in his dorm at Mediocre U and thinks to himself, "hey, being a doctor would be sweet." His 3.2 and 28 MCAT are reported to the 10 schools to which he applied in early October. He misses the deadlines for half of the secondaries because he is too stoned most of the time.

Susie gets interviews at all 20 schools, and very nervous about her chances for acceptance, takes out a loan to be able to afford to attend every one. Her interview skills are good but not fantastic, and she is offered acceptances at 10 schools ranging from The World's Best Medical School to San Juan State (she is fluent in Spanish).

Dave saves an old lady from being hit by a car (driven by another old lady) and breaks his leg in the process. He is a local hero for a day. Dave's alma mater, Mediocre U, extends him an interview invite even though he never actually paid his secondary application fee (the check bounced) and is very impressed with his laid-back nature and affability. He is extended an offer of admission.

Susie also interviewed at Mediocre U and was extended an offer of admission. The median stats for Mediocre U's accepted applicants were around a 3.7/32, because many people like Susie (who were nervous about their chances for acceptance) interviewed at Mediocre U - but did not ultimately end up attending. Because Susie received offers of admission from 10 schools, all schools factor in her incredible numbers when reporting their medians for accepted applicants. In effect, her numbers skew the true picture of the applicant pool. Dave's numbers carry less weight since he received only one offer of admission.

If anyone thinks this is incorrect (or better yet, knows why there are discrepancies), feel free to chime in... hence the purpose of the forum :)

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For starters, what you calculated was the mean which is different from the median. The median is the middle most value of matriculates or of those accepted, whichever they use. The median is used because it is not sensitive to outliers which would be the case for the two individuals that you referenced to in your post. This number does, however, distort the numbers because the median, in most cases, will in fact have a greater value than the mean because of outliers on the lower end; the outside could also be the case, the mean is greater because of outliers on the upper end.
 
Yes MSAR reports medians for the numbers of everybody accepted to that particular school, unfortunately I bet most of the top tiers and good state schools median accepted are very similar to median matriculated...due to the fact that not many ppl would turn down that school.
 
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For starters, what you calculated was the mean which is different from the median. The median is the middle most value of matriculates or of those accepted, whichever they use. The median is used because it is not sensitive to outliers which would be the case for the two individuals that you referenced to in your post. This number does, however, distort the numbers because the median, in most cases, will in fact have a greater value than the mean because of outliers on the lower end; the outside could also be the case, the mean is greater because of outliers on the upper end.

i actually didn't make any calculations - i was just throwing numbers out there to illustrate a point. i understand the difference between median and mean, and realize that different numbers show up in different places. i still contend that MSAR values are inflated.
 
Yes MSAR reports medians for the numbers of everybody accepted to that particular school, unfortunately I bet most of the top tiers and good state schools median accepted are very similar to median matriculated...due to the fact that not many ppl would turn down that school.

Good point about the top tiers and solid state schools :thumbup:
 
Yes MSAR reports medians for the numbers of everybody accepted to that particular school, unfortunately I bet most of the top tiers and good state schools median accepted are very similar to median matriculated...due to the fact that not many ppl would turn down that school.

i disagree. it's not about "not wanting to turn down a school." it's about only being one person, and only being able to attend ONE school. therefore, people with incredible stats that get in to 6 great schools can only attend one, while their stats inflate those of all 6 schools. therefore, stats are inflated even for the top schools.
 
I just wanted to make a point that I think is often missed around here, particularly with how worked up people get about numbers.

If anyone has taken a look at the recent MSAR (2009 ed), try to pop your eyes back into your head. I know that I was certainly shocked to see how much numbers have gone up in only the last few years (I have the 2007 MSAR). It seems like just about every school now has average GPAs around the 3.8 mark and MCATs that are 33-35. How is this possible, you might ask?

I haven't read the technical information in the MSAR regarding how they collect data (I'm not sure they give an exhaustive methodology anyway), but a quick comparison to the US News numbers shows a pretty significant discrepancy between median GPAs and MCAT scores vis-a-vis the MSAR.

What I suspect is happening is that the MSAR is reporting median statistics for all accepted students rather than just matriculants. This has the effect of inflating numbers because a school can honestly say "the median GPA for accepted students was 3.8" even if the median GPA for people who actually chose to go there was 3.6. Here's an example of how this would work:

Susie graduates from Cal Tech with a 4.0 and is disappointed with her 43 MCAT. She applies early and broadly to 20 schools, and returns secondaries for all 20.

Dave wakes up one day in a cloud of marijuana smoke in his dorm at Mediocre U and thinks to himself, "hey, being a doctor would be sweet." His 3.2 and 28 MCAT are reported to the 10 schools to which he applied in early October. He misses the deadlines for half of the secondaries because he is too stoned most of the time.

Susie gets interviews at all 20 schools, and very nervous about her chances for acceptance, takes out a loan to be able to afford to attend every one. Her interview skills are good but not fantastic, and she is offered acceptances at 10 schools ranging from The World's Best Medical School to San Juan State (she is fluent in Spanish).

Dave saves an old lady from being hit by a car (driven by another old lady) and breaks his leg in the process. He is a local hero for a day. Dave's alma mater, Mediocre U, extends him an interview invite even though he never actually paid his secondary application fee (the check bounced) and is very impressed with his laid-back nature and affability. He is extended an offer of admission.

Susie also interviewed at Mediocre U and was extended an offer of admission. The median stats for Mediocre U's accepted applicants were around a 3.7/32, because many people like Susie (who were nervous about their chances for acceptance) interviewed at Mediocre U - but did not ultimately end up attending. Because Susie received offers of admission from 10 schools, all schools factor in her incredible numbers when reporting their medians for accepted applicants. In effect, her numbers skew the true picture of the applicant pool. Dave's numbers carry less weight since he received only one offer of admission.

If anyone thinks this is incorrect (or better yet, knows why there are discrepancies), feel free to chime in... hence the purpose of the forum :)

Wow, and I thought I was the only Wildcat with nothing better to do than surf SDN ; )
 
Wow, and I thought I was the only Wildcat with nothing better to do than surf SDN ; )

hey, at least i waited until after interview season was over to join ;)
 
while I haven't looked anything up yet (and you explained your point pretty well) I would like to be the first to dissent. I just don't think this is true. For example, the MSAR MCAT mean for one of our local schools is ~27, and I am positive that this doesn't reflect those who withdrew.
 
while I haven't looked anything up yet (and you explained your point pretty well) I would like to be the first to dissent. I just don't think this is true. For example, the MSAR MCAT mean for one of our local schools is ~27, and I am positive that this doesn't reflect those who withdrew.

respect. are you sure about that number though? i don't recall seeing any non-PR schools that had medians that low. but it was a few weeks ago that i looked.
 
Haha great story.

I think your analysis migth be correct.
 
Looks like I'm going to have to devise a plan with some old ladies...
 
cute story, but it wasn't necessary to get your point across haha
 
Looks like I'm going to have to devise a plan with some old ladies...

haha, sorry Dave, didn't know you browsed these forums :oops:
 
respect. are you sure about that number though? i don't recall seeing any non-PR schools that had medians that low. but it was a few weeks ago that i looked.

I ought to think before I speak... I remembered as I was reading your comment that I was looking at USNews data. I was confused because until a week ago when I read it (in book form) I always associated the MSAR with a text and USNews with a website. My bad.

But I will check it out tonight and let you know for sure. The school that I am talking about would average almost 30 for acceptees and ~27 for matriculants, because most of the better qualified students opt for the cheaper state school.
 
Keep in mind, US News uses old data (in which case the GPA and MCAT of all schools would be lower than they are now) and means, instead of medians. The means will most certainly be lower than the median due to the outliers that are accepted with very low stats.

I suspect that the median of matriculants at top 10 schools is very close to the median of accepted applicants (ie around a 36). The median of schools in the 10-25 range is probably close to 34-35. If you use Northwestern, for example, the average MCAT of matriculants last year was 34.2 (so the median was probably slightly higher).
 
Applicants are shooting for acceptances, so I think it's safe and accurate to compare your stats to the stats of accepted applicants even for the less selective schools. From what I've heard during my interviews, it seems like admissions offices already have a certain number of acceptances they are willing to give out in total. Even if someone decides not to go there, that's one less acceptance that will go out overall.

I think matriculant means/medians are more useful if you are already accepted and want to know if you would be able to keep up academically compared to your fellow students.
 
i disagree. it's not about "not wanting to turn down a school." it's about only being one person, and only being able to attend ONE school. therefore, people with incredible stats that get in to 6 great schools can only attend one, while their stats inflate those of all 6 schools. therefore, stats are inflated even for the top schools.
You are wrong sorry...
 
You are wrong sorry...

in what way? numerically, my assessment makes sense. "better" applicants, with "better" numbers, who gain more acceptances, skew the statistics for median GPAs/MCATs of accepted students.

now, if you want to make the argument that people with better numbers don't get more acceptances (which is possible, since they may in the aggregate apply to more selective schools), then I'm willing to listen. but i don't hear you making that argument. i just hear the sound of your brain melting as you struggle to understand my math skillz ;)
 
in what way? numerically, my assessment makes sense. "better" applicants, with "better" numbers, who gain more acceptances, skew the statistics for median GPAs/MCATs of accepted students.

now, if you want to make the argument that people with better numbers don't get more acceptances (which is possible, since they may in the aggregate apply to more selective schools), then I'm willing to listen. but i don't hear you making that argument. i just hear the sound of your brain melting as you struggle to understand my math skillz ;)

EDIT: Upon reviewing your other thread, I see that we are actually in agreement. Who knew. :p


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I understand your logic, and see your point...and boy would I be glad if it was provable somehow, but I highly doubt that the scenario you've set up is how it really is. Here's why I think that the AAMC** does not count applicants multiple times based on which schools they have been accepted to:

The AAMC is the clearinghouse and central intersection point for all of the application process information for all medical schools. Medical schools which use the AMCAS application system report which applicants have accepted a spot at their school to the AAMC. This is how the AAMC tracks who has, and who hasn't held on to all but one acceptance come May 15th. This information is recorded by AAMC in your applicant file, indexed by your AAMC ID. Therefore, Susie Q 4.0 GPA 43 MCAT, AAMC ID: 12345678 has listed in her application file her GPA, MCAT and every school which has accepted her. The most logical way for the AAMC report data from this database is to run a simple script which goes through each AAMC ID file and return either 'yes' or 'no' if that person has been accepted to at least one AMCAS school. If the script returns yes, then the person's GPA and MCAT are added to the statistics for the 'nationawide accepted applicants' statistics. Now, if we are talking about the individual statistics from school to school in the MSAR, then you are right on the money. Accepted applicants are counted multiple times in multiple school's individual statistics.

I guess what I'm saying is that the AAMC has no need to ask every school to send them a median GPA and a median MCAT score for accepted applicants. They have all this information anyway. So, there no reason for them to count an applicant '20' times for each school they've been accepted to. In fact, it doesn't make statistical sense, since a nationwide median MCAT and GPA which has repeat counts in it isn't very useful to future applicants.

I would probably agree with your argument if the AAMC had to depend on schools to send them GPA and MCAT scores, but since that's not the case, I don't think there is a good logistical reason for the AAMC to go out of their way and count AAMC ID applicants multiple times when generating statistics.

EDIT: **Sry!! I made a typo. The double star (AAMC**) originally read 'MSAR' which is not what I meant!! I mean the overall GPA/MCAT averages for all acceptees published by the AAMC on their website. What you have said, if applied to the individual statistics of each school, is exactly true. The 'accepted applicant' stats from school to school in the MSAR does have major overlap due to multiple acceptances.
 
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