Ask the grumpies: Class size research

Fiona McQuarrie asks:

Just curious whether you have any opinion on the Hoxby class size research (in Connecticut) that Gladwell discusses.

Here’s an interesting summary of class size research from Brookings.  It is worth reading if you’re interested in the topic.

There’s a lot of stuff going on with class size research (it is, in fact, the topic going through the Stock and Watson undergraduate econometrics textbook because it has been attacked through most standard econometrics methods).

A couple of important things to note about external validity for these studies:

1.  Natural experiments (and, indeed, standard experiments) are only as externally valid as the experiment itself.  That means that a study that finds an effect on kindergarteners is not going to necessarily say much about high school students.  We know a lot about class size and K-3, we don’t know so much about middle grades or higher.  This particular experiment is on 4th and 6th grade.  It argues that it gets cumulative effects of class size by cohort size, but when a cohort is expected to be a certain size, districts may plan differently by moving bad teachers to small cohorts and good teachers to larger cohorts etc.  They may do the same with aides when deciding where to make a class-size split, or they may make specific decisions about where to put the problem kids or whether to do tracking or clustering.  That kind of planning would completely wash out the effect in a way that you would not see if all classes were restricted to a certain size because of a policy change.  That kind of planning is more likely to be going on in the type of natural experiment that Hoxby examines in this study.

2.  Class size decisions are not made in isolation.  A policy asking for extra money from the federal government to reduce class size is going to provide different results than a policy that is forced to take that extra money out of another budget.  Generally, research suggests that, believe it or not, most schools are doing the best that they can with the budgets that they have.  When you give them an unfunded mandate, outcomes are hurt in ways that they wouldn’t be if you gave them a funded mandate.  Hiring more new teachers and buying portables while taking money away from other programs may end up having a negative effect even if smaller class-sizes are beneficial.  The type of natural experiment Hoxby is looking at is one of these situations– the budget isn’t changing based on class-sizes, they get the same $/kid whether they’re in a large cohort or a small cohort.  The only thing that changes is the expense from economies of scale (whether they need one teacher/classroom or two).  That’s a different situation than one in which expenses for everything else stays the same but the district gets extra money to hire more teachers and buy portables.

So, do Hoxby’s results mean that class size is unimportant?  No.  They just show that it seems to be unimportant in the type of situation that she’s studying, one in which variations in elementary school class-size are caused by variations in cohort size.  That’s why there’s a large literature on this topic– the answer is different in different situations.  We need a lot of experiments and natural experiments to get the full picture.

Side note:  Caroline Hoxby is one of my personal heroes.  If I ever decide to give up this academia thing, I’m totally going to beg her for an RA job.  She is an amazing economist.  Also, rumor has it (aka multiple of her coauthors has mentioned) that she is one of those people who sleeps 4 hours/night every night because of low sleep need.

Brag about your kids and/or pets!

We haven’t had one of these posts since January 2013.  There’s been growth since then!

What wonderful and adorable things are your kids/pets doing these days?  What makes you beam?  What makes you smile?

Eeeeeeeeemail

Makin up a song about email in a chat log

#1:  my brain is exploding with email, I don’t understand
whyyyyyy
whyyyyyyy so much email

#2:  why are you getting so much email?
who is sending it?

#1:  many peeps

#2:  networking peeps?

#1:  all sorts of peeps. Some is forwarded from [university]. Some is colleagues. Some is friends, some is listserv, some is “your order has shipped”, some is my mom

#2:  “your order has shipped” is always nice.  Does your mom have an unsubscribe button?

#1:  hahaha unsubscribe mom from sending me stuff she thought I might like that is either irrelevant or I thought about it 3 years ago. Sigh.

[begin music]

My password expires in 30 days…. would you please allow us to use your stimuli (sure!), would you like to read these books or attend this sale or be a co-author, the conference information has changed….. eeeeeemail.

The third co-author needs to talk to you, here is your lease, here is the name of a headhunter, our baby is cute….. eeeeeeemail.

(Bridge:  Here’s your receipt; would you mind taking this survey?)

Your review is due, someone’s changing their email address, times for riding….  eeeeeeeeemail.

Sing it with me, y’all!  (#2 also has 200+ emails to go through right now…)

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Before and after: Housing edition

Before:  big, cheap, stupid, and located in hell

After:  small, expensive, smart, nice and in walking distance to everything– restaurants, parks, shopping, grocery stores, public transportation, THE LIBRARY

I think Imma need these.  You put them under your bed frame legs to get your bed up higher so you can store more stuff under there.   I have some plastic drawers that I can stick under there.  I might get some cardboard ones for sweaters (so they can breathe). or I might put books under there. Or general stuffas! I feel like “random crap” should maybe go in there rather than valuable shelving. Good times, good times

Downsizing sucks.  It’s work. Boring and tedious.

That’s it.

I refuse to talk anymore about apartments. You don’t even know how burned out I am.  It’s MY apartment and even I’m tired of it.

I have one.  It’s nice.  Though I won’t really know how nice it is until we’ve lived there for a while.

The end.

Next up:   I refuse to talk about moving.

Link love

This has been a pretty crazy week.  Our hearts go out to a lot of people.

How black people are portrayed in mainstream media

America is not for black people  :(

Jesus indeed

What sort of white person do you want to be?

Ugh– some of the great tweets from the Ferguson debacle have had their owners accounts go silent.  Twitter harassment SUCKS.  Racism SUCKS.  F the patriarchy.

Medieval POC’s math and science week

Robot hugs explains the smile thing

women against feminism parody account

squid lady parts

concern trolling sucks

Marvel vs. DC

Cat and baby

sometimes you just want pretty pictures of books

here, this

Someone passed her thesis defense.

 

I'm all caught up, said no academic ever.

 

Googly eyes

Q:  average time to completely furnish a 15 room house

A:  No doubt far less than what it took us to furnish our smaller house!

Q:  ran out of cereal and bread what should i have for breakfast

A:  eggs!  or cake…

Q:  do lecturers work through summer

A:  Often they do, but not always.

Q:  why do people make fun of gifted children

A:  Because the world is a terrible terrible place.

Q:  what is a moms least favorite chore

A:  Depends on the mom.  Is your least favorite chore the same as everyone else’s?  (My least favorite chore is probably vacuuming because I’m hella allergic to dust.)

Q:  can i get a “c” in a graduate school class

A:  Yes.

Q:  are 9 month contract professors required to fill out fmla paperwork for the summer

A:  Probably not, but check with your school’s HR just to be sure.

Q:  ways to answer roll calls

A:  Here.  Present.  Yes.  Ya Vol mein frau doktor!

Q:  why doesn’t my balance in your checkbook doesn’t match up

A:  Why do you have my checkbook?

Q:  a toddler that sleeps a lot mean not that intelligent?

A:  Of course not!

How does your toilet paper roll?

My first roommate that I shared a bathroom with took me aside one day, exasperated, and told me I was putting toilet paper rolls back all wrong.  I’d been flipping them under without even thinking about it, possibly because that’s what they do at my house.  My family has always been a bit different (my father is an immigrant), so I figured I wasn’t doing it the American way or something.

The next year, I had a different roommate.  After a few weeks of conscientiously making sure the toilet paper was flipped over when I put in a new roll, I noticed the toilet roll flipped under.  So I asked my roommate about it, and she said not only had she been putting in rolls flipped under herself, but she’d been changing my rolls because I was *doing them wrong* and found it seriously annoying but didn’t want to bring it up with me.

The next two roommates I had, I brought up this question the first day because I figured this was something I didn’t care much about, but a lot of people have strong feelings about it.  (Me, I’m just happy that the roll gets replaced at all!)  They both thought I was crazy for even thinking about it.  (And indeed, with them, sometimes the roll would be over, and sometimes under, almost at random.)

How about you?  Is this something you have strong feelings about?  Are there other kinds of habits like this where your way is the right way but other people do it wrong?  (Squeezing toothpaste from the bottom is my hobby horse.)

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