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Why are there so few physics majors?

by Wheelwalker
Tags: college, major, majors, mathematics, physics
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twofish-quant
#37
Jan26-12, 06:56 AM
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Quote Quote by ZapperZ View Post
I'm surprise to see such things coming from you. Are you telling us that you cannot tell the difference between ONE data point versus MANY data points? A survey tries to sample a lot of data points, the more the better.
No. It's not. My wife has a Ph.D. in education, so they have to deal with this all of the time, and I learn a lot from reading her books.

People aren't rocks so the methodology in dealing with people are different from those dealing with rocks. If you are dealing with a uniform sample and you are interested in a specific question that can easily be quantified (i.e. scores on a test), then you can statistically calculate how many samples you need to get a good sample, and doing more than that is a waste of time. The statistical error goes as the square root of the number of samples which means that once you have a large number of samples, then adding more isn't going to help, and if there is a non-sampling bias in the survey that's larger than sampling error you are spending a lot of effort for nothing.

Now if you are dealing with non-uniform samples, then statistics sometimes doesn't work, and then you have to go into interviews and other methods. The thing about interviews is that you can go really deep. For her Ph.D. dissertation, she ended up using interviews of four people, and I've known people that have done dissertations using *one* person as a sample. (What you can do with one person that you can't do with several hundred is to follow them around for two months and watch what they do.)

It's ***not*** statistically representative, but you are often dealing with in which you are interested in the deep details of one person rather than very shallow information about 1000. Also with interviews, you can do things like figure out someone's deep psychology, which is something that you can't do with a survey. The other thing with people is that everyone is different, which means that statistical representativeness isn't sometimes useful.

The other thing is to conduct a valid survey is amazingly tough. Asking the right question can be tough. For example, if you want to ask if college is too expensive it seems to make more sense to ask college freshmen parents than college freshmen.

And you're asking why your data point is different than a collection of MANY data point? You honestly cannot see the difference?
I can see the difference, and I don't see why I should trust my own eyes less than a group of people that I've never heard of. For that matter, one of the reasons I may be more useful than a survey done by people you've never met is that I'm here and you can ask me questions.

History vs. physics prof: A physics professor tends to being in MORE external funding.
Sure, but why are people willing to find physics professors more than history professors? I think it has something to do with the fact that physics profs can discover things with more obvious economic benefit than history profs.

Physics versus business/finance: See last part of my argument above. A finance professor has more opportunities to go elsewhere..
Right, it's all about the money.
twofish-quant
#38
Jan26-12, 07:00 AM
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Also I've seen so many bogus college surveys that the amount of trust that I put into them is quite low. If you want to see what schools actual employment rate is like, don't trust a survey. Sit down with a few alumni and talk to them over lunch.
ZapperZ
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Jan26-12, 07:13 AM
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Quote Quote by twofish-quant View Post
Also I've seen so many bogus college surveys that the amount of trust that I put into them is quite low. If you want to see what schools actual employment rate is like, don't trust a survey. Sit down with a few alumni and talk to them over lunch.
And using that methodology, you should also believe in supernatural phenomena and other pseudosciences.

Zz.
atyy
#40
Jan26-12, 07:34 AM
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Are there really people who consider college not a trade school in the broad sense - ie. it makes it more likely that one will have a job that pays reasonably? I personally know very few who thought that college was not a trade school, and they have all changed their minds from 20 years ago.

Not sure about the beer part though

Maybe relevant: Employment status of the civilian population 25 years and over by educational attainment
twofish-quant
#41
Jan26-12, 08:32 AM
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Quote Quote by ZapperZ View Post
And using that methodology, you should also believe in supernatural phenomena and other pseudosciences.
I don't see why. Note that a typical social scientist isn't interested in researching whether there are UFO's or not, they are interested in researching what people *believe* about UFO's, and the research methods for figuring out what people *believe* are quite different from the research methods for figuring physics problems. There are some interesting philosophical issues here, and if you really think that qualitative social science methodology leads to pseudoscience, put on your asbestos suit, and there are people that can argue the issue better than I can.

Just picking some books off my wife's bookshelf. Bogdan and Bilken's Qualitiative Research Methods for Education. Strauss and Corbin's Basics of Qualitative Research. If you believe that "anything not statistical is pseudoscience" you can argue with them.

(And if social science is pseudoscience, then why are we teaching it in universities? For that matter, universities often have theology and religion departments in which you have pretty smart people that *do* believe in the supernatural. Should we get rid of those?)

The other thing is that it's common in astrophysics to "forget statistics." A lot of what we believe about stars is based on one sample (the sun) and a lot of what we believe about supernova is also based on one sample (1987A). It would be nice if we had 100% data on all supernova and all stars, but we don't, and the fact that we really have no reason to think that neutrino emissions in the sun are typical of other stars doesn't mean that HR diagrams are "better." I use my life to figure out what is going on with other people in the same way that I use the sun to figure out other stars. Other stars are different, but they are just too far away for me to get good data.

Also one thing that I like about money is that it makes things more objective. One reason that I believe that there aren't many people willing to pay cash money for pure enjoyment of astrophysics is that if there *were* such a market demand, I'd quit my job tomorrow and become a free lance tutor of astrophysics. What I'd do is to take the courses that I've taught at the University of Phoenix or University of Texas at Austin, and if people were willing to give me the same money that they give UoP or UT Austin and I were able to spend the same amount of time doing it, then that would be more than enough to lead a comfortable life.

The problem with that plan is that I can't give them the piece of paper that they can use to get cash money, and if they can't get cash money, they can't pay me cash money, and the number of people that are willing to pay me cash money for astrophysics as a hobby isn't enough to make things work. One other data point is Fathom and similar efforts. Around 2000, a number of major universities started online initiatives to teach enrichment courses and all of these were shut down after massive losses. It seems that people won't pay money for these courses if there isn't money to be made. By contrast there are tons of online MBA's, of various quality.

There's also the experiment I did at UT Austin. I taught a one unit class, which a lot of seniors used to get the one credit they needed to graduate. So what happened was that on the first day of class, I told everyone that if they just wanted to take the class for the credit, this would be the minimum amount of work that they needed to do, and they could finish it all in one month. If they wanted to learn more stuff they could stick around after that one month. Typically, the enrollment numbers went from 200 to about 10 after that month passed. (Also UT Austin is still teaching the class, so you scan ask people there for current numbers.)

About reality, we can argue a lot about the nature of reality and evidence. What matters is when you go up to the edge of a cliff and are willing to jump onto a dry lake bed to avoid a herd of stampeding buffalo. I'm not because I think gravity exists, and if I do it, I will die. Similarly, if you could convince that most university students were interested in pure learning then there is water at the bottom of the cliff, and I'd quit my job tomorrow and go into free lance tutoring. (Seriously I would.) Now, personally, I think it would be economic disaster for me if I did this, but if you convince me that gravity doesn't exist, then I'll jump. (Also, I know of a number of Ph.D.'s that make a good living teaching physics free lance. They don't live in the US but rather work for cram schools in East Asia.)

Now, I'll jump eventually. If they problem is that people want to turn my tutoring into cash that they can pay me with, I suspect that someone will figure out how to do that in the next five to ten years. If the US goes to an East Asian type testing system, then everything blows open.

Once someone figures out the cash part, then then concrete at the bottom of the cliff becomes water, and there's a herd of stampeding buffalo running toward me, so at that point reality says to jump.

Now I'm crazy. Sometimes people think I'm delusional. Other times, people think I'm visionary. I think I'm both, but one thing I care a lot about is the nature of truth and reality. Because, if you are not seeing the truth, you end up dying, either figurative or literally.

I don't think we can keep doing things the way that we've always done then. We can't go back to the 1950's because in the 1950's, the internet didn't exist. I happen to think that at some point there will be water at the bottom of the cliff, and the buffalo are going to come, so I'm preparing to jump, just not now. If that's not your reality, then go with what you see, and we'll see what happens.
twofish-quant
#42
Jan26-12, 08:43 AM
P: 6,863
The other thing, if you *do* believe college satisfaction and employment survey data at face value, then this *really* is the financial equivalent of jumping off the cliff.

One reason I trust face to face interviews when it comes to figuring out someone's beliefs more than I do surveys, is that people find it easy to lie on surveys. Someone asks you if you are employed and how much money you make, people just don't feel bad about checking the wrong box. People find it much, much harder to fudge the truth, when you look them in the eye, and even if do it, there are a lot of unconscious cues. (There are a few pathological liars that can control their behavior, but they are extremely rare.)

So if I ask "are you satisfied with your education and your job" and it's a survey, I don't know what to make of it. If I'm eating lunch with them, their mouth may say "great!!!" but their eyes may tell a different story.
twofish-quant
#43
Jan26-12, 08:59 AM
P: 6,863
One other excellent book is Gall, Borg, and Gall Educational Research: An Introduction. Chapter one is an excellent introduction into the relationship between quantitative and qualitative research and has a section on the nature of reality (seriously). Chapter 15 has a deep discussion on the various qualititative research traditions. There is a whole field called "life history research."

Also, one reason that I like the "university as a trade school" philosophy is that you find all of this stuff *incredibly* useful when looking for, getting, and keeping a job. The problem with whatever the alternative is, is that it forces you to become very silo'ed, whereas "trade school" opened my mind to very deep ideas.
ZapperZ
#44
Jan26-12, 09:17 AM
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Quote Quote by twofish-quant View Post
I don't see why. Note that a typical social scientist isn't interested in researching whether there are UFO's or not, they are interested in researching what people *believe* about UFO's, and the research methods for figuring out what people *believe* are quite different from the research methods for figuring physics problems. There are some interesting philosophical issues here, and if you really think that qualitative social science methodology leads to pseudoscience, put on your asbestos suit, and there are people that can argue the issue better than I can.
There is a difference between not accepting something in principle, versus acknowledging that while the principle is sound, how it is applied could be suspect. You appear to reject ANY kind of statistics wholesale. And what's worse, you appear to think that you anecdotal evidence trump over everything else!

That is why I said that using your methodology, one could justify all kinds of pseudoscience phenomena, because after all, a person only needs to "see it with his own eyes" and accept it, no matter whether is valid or not.

I can easily describe scenarios where your anecdotal situation is really not reflective of the general trend. Your sampling of one single data point could easily be the exception rather than the rule. After all, if one asks all the "alumni" of students of Phil Anderson, one can easily see that all of them ended up with exceptional careers in prestigious institutions. Does that mean that a career in theoretical physics has that bright of a future? Absolutely not! Yet, using your "logic", this is perfectly valid and trumps over all other statistics and reality of such a career!

So if you think you can find fault in statistics, I can easily counter that by finding faults to your methodology as well!

Zz.
atyy
#45
Jan26-12, 09:30 AM
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Quote Quote by ZapperZ View Post
I can easily describe scenarios where your anecdotal situation is really not reflective of the general trend. Your sampling of one single data point could easily be the exception rather than the rule. After all, if one asks all the "alumni" of students of Phil Anderson, one can easily see that all of them ended up with exceptional careers in prestigious institutions. Does that mean that a career in theoretical physics has that bright of a future? Absolutely not! Yet, using your "logic", this is perfectly valid and trumps over all other statistics and reality of such a career!
But if Phil Anderson's students' students did not end up with exceptional careers in prestigious institutions, that would show your counterexample false. Do you have evidence that Phil Anderson's students' students ended up where you think they did?
ZapperZ
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Jan26-12, 10:18 AM
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Quote Quote by atyy View Post
But if Phil Anderson's students' students did not end up with exceptional careers in prestigious institutions, that would show your counterexample false. Do you have evidence that Phil Anderson's students' students ended up where you think they did?
They sure do! All of them!

But even if I find ONE that didn't, what does it tell you? Is that ONE example enough to nullify all the rest? Besides, isn't this also doing a statistical analysis, albeit at a smaller sampling?

I find it frightening that some of us think we have a grasp of our world based on a SINGLE data point AND use that to advise others! I find that to be highly irresponsible!

Zz.
Dembadon
#47
Jan26-12, 10:43 AM
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... My question is: why are there so few physics majors? ...
It has been my experience that the average student at my university prefers the path of least resistance. Science and engineering programs take a great deal of effort and I believe a lot of students will be happy to just make it through their college experience with good enough scores to please family, friends, and potential employers, no matter what their major is. At least that's the impression I've been getting for the past couple years.

That said, physics is certainly not one of the paths within the realm of least resistance!
atyy
#48
Jan26-12, 11:07 AM
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Quote Quote by ZapperZ View Post
They sure do! All of them!

But even if I find ONE that didn't, what does it tell you? Is that ONE example enough to nullify all the rest? Besides, isn't this also doing a statistical analysis, albeit at a smaller sampling?

I find it frightening that some of us think we have a grasp of our world based on a SINGLE data point AND use that to advise others! I find that to be highly irresponsible!

Zz.
How do you know this?

But anyway, yes, I agree that good statistics are better than anecdotal evidence. However, two-fish's experience that people who go to university are extremely concerned about jobs is easily replicated. So if a survey comes up with a contradictory result, then one might ask for evidence that its methods were good, rather than giving it the benefit of the doubt.
ModusPwnd
#49
Jan26-12, 11:53 AM
P: 1,071
I think there are few physics majors because people dont like doing physics and math for the most part. Also, the major is best for people who want to go to grad school and most people dont want to go to grad school.
FroChro
#50
Jan26-12, 12:35 PM
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Quote Quote by ZapperZ View Post
T
I can easily describe scenarios where your anecdotal situation is really not reflective of the general trend. Your sampling of one single data point could easily be the exception rather than the rule. After all, if one asks all the "alumni" of students of Phil Anderson, one can easily see that all of them ended up with exceptional careers in prestigious institutions. Does that mean that a career in theoretical physics has that bright of a future? Absolutely not! Yet, using your "logic", this is perfectly valid and trumps over all other statistics and reality of such a career!

So if you think you can find fault in statistics, I can easily counter that by finding faults to your methodology as well!

Zz.
You could interview those guys, find out they had same advisor, and then get more information about him - it is about making sense out of it.

You can't use statistical approach to non-statistical data.

If a measurement is incompatible with accepted theory, first question the experiment. If statistic is inconsistent with what I know about the world, first I question the statistic.
FroChro
#51
Jan26-12, 12:49 PM
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Quote Quote by ZapperZ View Post
I find it frightening that some of us think we have a grasp of our world based on a SINGLE data point AND use that to advise others! I find that to be highly irresponsible!

Zz.
If you accept an advice is viable, you have to accept the world is comprehensible. To be so, there need to be some ''patterns''. Using them you can extrapolate from ''single'' data. (Not to say that word ''single'' is highly inappropriate.)

In other words, anecdotal evidence may be very deep and throughout -> you can analyze it and make a sense out of it. Statistics, while clearly extremely useful, may be very tricky to interpret.

To me it is more importatnt whether an evidence make sense than what kind of evidence it is. (Althought once you have a enough evidence that doesn't make sense you should maybe change a definition of sensible.)
ParticleGrl
#52
Jan26-12, 01:03 PM
P: 685
ZapperZ, lets refocus this idea of statistics back to the number in question:

Note that concern about paying for college has fallen to an all-time low of under 12%
Does this really seem like it can possibly be a valid number? In your personal estimation, how much weight should that number be given?

Most of my friends from highschool went to college, and made the decision of where to go based on cost. Most of my friends in college were nervous about the debt they were taking on. Many of my friends in graduate school were struggling mightily to pay down private loans they took out to pay for undergrad, etc. The students I taught who couldn't find jobs after undergrad were tremendously worried about defaulting on their loans. One of my coworkers wants to be a stay-at-home mom, but has been bartending for the last three years to pay off her college degree. I can't imagine how life could have provided me with a sample with a number SO different (80%-90%) from the survey.
ParticleGrl
#53
Jan26-12, 01:12 PM
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Quote Quote by Vanadium 50 View Post
If college is supposed to be a trade school with more beer, why are there history majors? Women's studies majors? And, to pick on the usual punching bag, art history majors?
Generally, I'd guess bad advising. If you grab an art-history major and ask them why they are doing it, you'll get something like "well, it doesn't really matter what your college degree is in, just that you have one. So you might as well study something that interests you." My highschool and college academic counselors told me the sheepskin was the thing, not the specifics of the degree.

The problem I find is that employers want to treat college like a trade school, so the students who treat it like one as well seem to have a leg up on those who don't. My friends in engineering programs nearly all got jobs in science/tech/engineering. My friends in science programs went on to get phds, and few of them have the sort of jobs they wanted.
ZapperZ
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Jan26-12, 01:38 PM
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Quote Quote by FroChro View Post
You could interview those guys, find out they had same advisor, and then get more information about him - it is about making sense out of it.
But this is my point! You can't simply accept some anecdotal evidence, and then generalized it! The fact that Anderson is a Nobel laureate, he gets to choose the top of the top of the crop for students, and the fact that his reputation alone is sufficient to land his graduates serious consideration (what I call pedigree) for many positions are ALL FACTORS that make this to NOT be the norm! Ignoring such a thing will give a seriously distorted view of the world!

When one looks at only ONE data point, one can't tell if such a situation is due to some exception or the rule, or a unique case. When you interview someone, was he/she describing the situation at that time?? Or is the situation still valid now? Do you get an idea of the TREND over a period of time to give you some indication of where things are heading?

Quote Quote by FroChro View Post
If you accept an advice is viable, you have to accept the world is comprehensible. To be so, there need to be some ''patterns''. Using them you can extrapolate from ''single'' data. (Not to say that word ''single'' is highly inappropriate.)

In other words, anecdotal evidence may be very deep and throughout -> you can analyze it and make a sense out of it. Statistics, while clearly extremely useful, may be very tricky to interpret.

To me it is more importatnt whether an evidence make sense than what kind of evidence it is. (Althought once you have a enough evidence that doesn't make sense you should maybe change a definition of sensible.)
See above.

I've been in this field for quite a while, and I think I'm perceptive enough to know many things about it. Still, I always look at many of the statistics that characterize different aspects of the field, and I continue to be surprised by many. I'm not saying that all of them are accurate, but whether one buys them or not, these still provide some amount of snapshot of a larger sampling than any one of us can do. As someone who advices students, I do not want my preconceive ideas of how I think things are going to trump over a series of consistent statistical results. Things change over a period of time, and often, they change very quickly, as we have seen the past couple of years.

At this point, I think people are misinterpreting my objection here. I object to putting anecdotal, single-data-point "evidence" ahead of statistics, or even ignoring statistics completely. I didn't say to ignore anecdotal evidence! I question the principle that no statistics can be trusted, and that ONLY anecdotal evidence is valid! It is why I asked for this clarification from twofish quant. There is a difference between dismissing all statistics as a matter of principle, versus stating that certain ones are no good due to various problems. If one believe the former, than one has to also dismiss all experimental high energy physics.

Quote Quote by ParticleGrl View Post
ZapperZ, lets refocus this idea of statistics back to the number in question:



Does this really seem like it can possibly be a valid number? In your personal estimation, how much weight should that number be given?
I wouldn't know. I have no knowledge of this number. If I were to go by MY situation, then I'd say all students are in great shape, because I graduated with ZERO debt. Now, how about THAT anecdotal evidence?

Zz.


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