Original post: I have a math PhD. In the United States, I can teach at a 4-year university or a community college without any additional training. However, to teach mathematics in high-school I must receive additional state-based certification.

My question has two parts:

  1. Why is certification required at the high-school level?
  2. Why is certification not required at the college level?

Edit: I like Willie Wong's improvement to this post:

Is there research backing up the empirically observed trend that teacher-training is necessary for teaching primary and secondary school, but not necessary for teaching at university level and above?

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    $\begingroup$ What does the state-based certification certify? Didactic or mathematical skills? $\endgroup$
    – Wrzlprmft
    Commented Mar 18, 2014 at 12:27
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    $\begingroup$ @Wrzlprmft: multiple things, including mathematical, didactic, and (in the case of at least New Jersey) something about physiology and hygiene which presumably has to do with teachers coming into contact with minors. $\endgroup$ Commented Mar 18, 2014 at 12:36
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    $\begingroup$ "I went through flight school, and I can fly a fighter jet for most branches of the US Military without any additional training. However, to drive a car in my home town I must receive additional state-based certification. Why?" Answer: (a) most potential drivers are not fighter pilots, and the legislators cannot be bothered to write in exemptions (b) there is unlikely to be institutional problems with a fighter pilot obtaining a driver's license (c) there is, after all, a little difference between the two, for example, the speed limit. $\endgroup$ Commented Mar 18, 2014 at 12:47
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    $\begingroup$ The question you want to ask is: "is there research backing up the empirically observed trend that teacher-training is necessary for teaching primary and secondary school, but not necessary for teaching at university level and above?" This question unfortunately is rather different from the question you actually asked, whose answer is more likely based on some voodoo performed on the desks of bureaucrats than any actual research. $\endgroup$ Commented Mar 18, 2014 at 12:51
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    $\begingroup$ @MattF., and I would contend that a PhD is anything but a certificate that the holder is able to teach... $\endgroup$
    – vonbrand
    Commented Mar 18, 2014 at 20:53

7 Answers 7


That is because teaching math and knowing math are different skills. Unfortunately, having a PhD in mathematics will not guarantee that a candidate will also be able to manage a class of 35 students, be able to design pedagogically and developmentally adequate lessons that progress in units, how to assess students, deal with the requirements for special education (i.e., IDEA) or English-language learners (e.g., California requires a special certification for ELD), and in general survive your first years of teaching without giving up.

These skills are usually taught during a teacher preparation program which is accredited by the state and follows teacher preparation standards (e.g., TPES for California). After competing a teacher preparation program, teacher candidates are recommended to the credentialing commission for their state (For this reason, it is not possible to automatically transfer credentials between states. Even if I am a teacher in California, I cannot just walk in an Oregon school and get a job). For example, in California you usually have to take 2/3 semesters worth of post-baccalaureate coursework to be able to qualify for a teaching credential. Each candidate has also to pass 4 qualifying exams (CalTPAs) if you want a multiple subject credential), a basic skills exam (CBEST), and 3/4 subject specific exams (subject CSET) before being recommended for a credential.

There are new programs that put you directly in a class (transition to teaching or TfA), but you will have to complete all the coursework if you want to have a credential (you can work temporarily with an emergency credential, but that will preclude you from tenure and to its perks). So, you can be in a classroom without a teaching credential but you will not able to keep your job. On top of that, a public school is not allowed to hire a teacher that is not cleared by the state teaching commission (especially after No Child Left Behind).

Private schools (not public charter schools) are exempt from these requirements and can hire who they deem more fit for the job. They act more like universities in that sense where evaluations by all stakeholders are more important that a state certification.

For the history of teaching credentials, basic skills exams date to the early 1800s and the introduction to teaching credentials to the 1930s. The credentials were modeled after the medical board licences or bar licences and were intended to strengthen the requirements to entering the teaching profession. Federal and state governments are, however, still working out some issues with the credentialing system. For example, NCLB (2002) introduced the requirement for a content area teacher to be highly qualified in the content area that he or she is teaching. This has been translated in requiring a math teacher to have a math teaching credential. Before that, a teacher with a teaching credential could teach whatever he or she was comfortable teaching (including an art teacher moving to math because her job was being cut) and to have a teaching credential in something (California use to issue general teaching credentials up until 1970's, so it is not uncommon to have old teachers with a general credential). Teacher unions do not have anything to do with credentialing teachers or with the introduction of requirements to become a teacher (they are usually more interested in protecting teachers with tenure). A good reading on the history of teaching in the US is 'Tinkering towards Utopia' by Tyack and Cuban.

I agree that having a teaching credential does not guarantee that you are a good teacher or know the subject you are teaching, but the same is true for doctors or lawyer. Nonetheless, if you want to practice medicine or law you need to have a licence. The same is true for teaching in the United States.


I'm sorry not having any empirical literature, but I try to explain the question by commong knowledge. (Feel free to downvote if this is not appropriate :))

Beside political reasons, I think there are two rules of thumb

  1. The more mature your students are, the less pedagogical knowledge you need.
  2. The more mature your students are, the more expertise on the subject you need

answering the question of the OP.

A little more detailed:

  1. If you want to teach younger students, you have to know a lot about cognitive development ("What task is suitable at which age"?). Also, the students are not that motivated due to e.g. puberty. If the students go the college/university, they have to decide for some subject and don't have to attend subjects they dislike. It is easier to explain a student something when he/she attends your class by choice. You have to concentrate more on technial aspects regarding the subject and less on motivatory aspects.
  2. A very small child is normally getting answer to all his/her questions by the parents - no matter what their job is. Just to have an answer to questions, you need in general no special profession. The more knowledge someone gained, the more difficult questions he/she can ask. So you really need to know as much as possible. (I think, there are (not only a few) people in academics saying that it is a waste of time of having a teaching certification since you "lost time" which could better be spent in gaining knowledge about your subject).

(I'm beware that this is more a "perfect world" explaination where all college/university students are mature.)

  • $\begingroup$ Regarding "lost time", my experience as an undergraduate was that most of the lecturers were teaching courses far distant from their research. I'm not saying there weren't better things they could do with their time than take teaching qualifications, but I doubt whether any knowledge they chose to gain in "their" subject would have an impact on their undergraduate courses. So possibly these academics are really arguing for more research and less teaching ;-) $\endgroup$ Commented Apr 21, 2014 at 14:11
  • $\begingroup$ ... but then, the number of results I learned in my MMath that were less than 80 years old was pretty small, and quite a few of those have crossed the 80-year boundary since (2 incompleteness theorems and the elementary theory of Banach spaces spring to mind as falling between 1920 and 1934). $\endgroup$ Commented Apr 21, 2014 at 14:24

I took the qualifying exams in my state to teach. All teachers need to pass the general literacy, along with the subject they intend to teach. For me, it was middle and high school math. (The former, about ages 10-13, the latter 13-18) My undergraduate degree was BSEE, electrical engineering, and even though I wasn't working as an engineer, I never lost my love of math. I had aced the math SAT (the exam most US students take to apply to college) with a score of 800. This is background.

I was on line to get in to take the high school level exam, having passed the middle school a few weeks prior. A woman next to me is visibly nervous, and shares with me that she teaches English, but wants to teach middle school math. She said she is back for her third attempt. I can't really describe the emotion I felt. Safe to say, I hope she failed. Would you want your 8th grader to be taught by someone who needed 3 tries at passing an exam like this? More important, if you can't pass this the first time, do you really feel comfortable enough to teach the subject?

To circle back - teaching grade or high school needs the course work to have teaching skills presumably learned as part of the certification process. In my opinion, that's fine, but the level of understanding required to teach the subject should be higher. The high school level exam contained virtually no calculus, and in hindsight, barely differed from the middle school exam. I'll take an individual with a masters in mathematics over a certified teacher who bared passed the exam any day.


This seems to me to be two questions.

Is there research backing up the empirically observed trend that teacher-training is necessary for teaching primary and secondary school, but not necessary for teaching at university level and above?

Not as far as I know. I do know there is research that strongly suggests that different teaching methods at the university level lead to different learning outcomes from the students. For a summary of some of this research, see Eric Mazur (warning: long) talk about how his teaching changes. There is also research suggesting that "interactive teaching methods" "double" learning gains for students.

Both of these are relevant because they suggest that there is a body of knowledge that describes good teaching at the university level, and so it stands to reason that this body of knowledge is something that can be taught to people, and one way to do that would be through an teaching credential. I have some friends who are working on this exact issue at a few different universities.

As for the commenter who says that good teaching is not necessary at higher grade levels, I completely disagree. For example, Carnegie Mellon University had a 5% pass rate for their remedial math courses. With an increased emphasis on math mindsets, they have increased this pass rate by 10 times in the first year alone (unpublished research, look for it in a year or so). This says that how and what one teaches matters, even at the higher levels!

Why do universities and colleges not require teaching credentials?

For this, I would look at how universities and colleges get their money to operate. They receive part of their money from tuition (ie. which is dependent at least partially on the outcomes of their teaching), but it is my understanding (although I do not have time now to search for the relevant research), that universities receive much of the money they use to operate from operating grants & endowments (often of limited accountability on any measure) and from funded research. Only one of their funding resources has anything to do with the outcomes of their teaching, and so there is less incentive to focus on improving their teaching, which would be the obvious purpose of introducing a teaching certificate.

As for k-12 schools, basically the only point of the money given to them (aside from the fact it gives millions of students something to do while their parents work) is that they are expected to teach students. Hence, the k-12 system has a much stronger incentive to require capacity for teaching, which again, the assumption is that a teaching certificate improves.


The history of this topic in the US is long and complicated. It differs from state to state, and also between rural and urban areas. In rural areas before about 1850, teachers were in short supply; a prospective schoolteacher had to have a very basic education, and also would have to pass an oral exam administered by the local school board. In the second half of the 19th century, cities began to "professionalize" teaching. First there were "normal departments" within high schools, and later these became independent normal schools. Around 1900-1930, there started to be schools and colleges of education within universities, and eventually many of the more prestigious ones became graduate schools of education. As early as 1905, California required five years of college for prospective teachers.

One can read all this as simply a gradual raising of professional standards, and a lot of these changes did coincide with the great era of progressivism. On the other hand, there were certainly winners and losers in the process, and one can tell an economic story. Supply and demand fluctuated. For example, during World War I, many women left the teaching profession to take the better-paying jobs vacated by men who had been drafted. This led to a shortage of teachers, and teachers' pay went up. During the Depression, there was an oversupply of teachers, and credentialing was used by many districts to control the supply.

Economic liberals such as Milton Friedman have argued that the proliferation of licenses (for morticians, auctioneers, cosmetologists, ...) allows the profession to set up a cartel similar to a medieval guild, so as to artificially limit supply and drive up prices. But I'm not sure that this argument applies well to high school teachers. If it did, you would expect that the credentials would have been created at the behest of teachers' unions. Teachers unions have existed for a long time (e.g., the California Teachers' Association since 1863), but it was only relatively recently that they became the political behemoths that they are in a state like California, where CTA is described as the fourth and most powerful branch of the state government. It wasn't legal for teachers' unions to carry out collective bargaining until about 1960, which is many decades later than the creation of certificates.

My best read on the history is that credentialing was driven by the institutional self-interest of the schools providing training to teachers, as these gradually evolved from normal departments of high schools to graduate schools of education. These institutions employed a lot of professors and administrators, and the livelihood of those people was crucially tied to requiring specialized education coursework for prospective teachers.

Taking California as an example of the current system, if you want to teach high school math, you need a single-subject teaching credential. This requires the following:

  1. A bachelor's degree.

  2. College coursework in education, which is often taken while the prospective teacher is an undergrad.

  3. Passing a standardized test of basic skills (CBEST).

  4. Passing a standardized test showing competence in math (CSET).

  5. The above requirements get you a five-year preliminary credential, after which you need to jump through more hoops (education courses or testing) to get a permanent credential.

I would assume that anyone well qualified to teach math would easily satisfy requirements 1, 3, and 4. But the evidence does not provide much support for the requirement of educations courses. A study by Goldhaber using a a value-added methodology finds that although there are huge differences in effectiveness between teachers, only about 3% that variation is explained by objectively measurable factors including education and experience. In defense of the people who originally set up the credentialing system, it should be pointed out that this evidence is very recent, and there was probably no reliable evidence for or against the effectiveness of education coursework at the time when the requirements were set up; Goldhaber discusses the earlier studies, which were flawed methodologically.

Sources I read:

"The dubious case for professional licensing," http://economix.blogs.nytimes.com/2013/10/11/the-dubious-case-for-professional-licensing/?_r=0

Angus, "Professionalism and the public good: a brief history of teacher certification," available online by googling

Goldhaber, "The mystery of good teaching: surveying the evidence on student achievement and teachers' characteristics," http://educationnext.org/the-mystery-of-good-teaching/


Teachers' unions are the main political forces behind certification requirements in U.S. public high schools.

If certification is as effective as graduate degrees in promoting teaching quality, it's not very effective.

$ $

I previously said "certification is required in U.S. public high schools because the teachers' unions have promoted it," but I retract that after the historical criticism in the comments.

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    $\begingroup$ In another answer (matheducators.stackexchange.com/questions/130#312) I quote a paper which argues that masters degrees in maths are effective for teaching maths. I have not analysed the quality of that paper or of the report that you cite, of course. $\endgroup$ Commented Mar 18, 2014 at 15:11
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    $\begingroup$ Interesting. That excerpt shows that a master's degree in math is effective, but also suggests that a master's degree in education (which is far more common), a teaching certification, and a math teaching certification are all ineffective. $\endgroup$
    – user173
    Commented Mar 18, 2014 at 15:23
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    $\begingroup$ I believe there were certification requirements long before teachers unions existed or had any power. Isn't it at least as consequential that school boards (fundamentally political) need to prove to their constituencies that they're doing something? Improving things? Quality control? $\endgroup$ Commented Mar 18, 2014 at 21:06
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    $\begingroup$ Would you mind backing up the first sentence? And it would be helpful to summarize findings of the link in the second sentence in case it rots. $\endgroup$ Commented Mar 18, 2014 at 21:13
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    $\begingroup$ @Jon Ericson: I start with "Qui bono?" Here are some relevant quotes. "The NEA believes that alternative pathways must be equal in rigor to traditional programs". Likewise the AFT: "All future teachers should be required to meet a universal and rigorous bar that gauges mastery of subject-matter knowledge, much like the bar exam" nea.org/tools/16578.htm and aft.org/newspubs/press/2012/120212.cfm $\endgroup$
    – user173
    Commented Mar 19, 2014 at 12:28

It related to universities policy. It assumed that all departments hire course experts. Then departments must classify and distinguish the pedagogic ability and scientific capability.

1- Interdependency of colleges in practice cause this matter.

2- Also applied mathematics for each departments refuse any standard mathematics. Then departments hire teachers that are dominant about applications of mathematics there.

3- In assumption teachers in colleges are educated at high levels and have sufficient pedagogic and course knowledge.

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    $\begingroup$ I don't think there is a meaningful distinction between "theory" and "practice". Also, I don't know what it would mean that applied mathematics refuse(s) any standard mathematics. Altogether, it's not course knowledge, but subject knowledge, usually at a level far beyond any courses that will be taught. $\endgroup$ Commented Mar 18, 2014 at 21:05
  • $\begingroup$ You misunderstand me. Theory in my sentence means mental base of teaching. $\endgroup$
    – Huseyin
    Commented Mar 18, 2014 at 21:51
  • $\begingroup$ Applied mathematics is any subjects that departments literature widely use them. For example social sciences applied mathematics concentrate on optimization and decreasing of proves of mathematical rules. $\endgroup$
    – Huseyin
    Commented Mar 18, 2014 at 21:55

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