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johnhess

639 karma · joined December 22, 2011

[ my public key: https://keybase.io/jthess; my proof: https://keybase.io/jthess/sigs/BAcytrWh1J-g0_haNFK8usciyCuLII-kPiO8IFobt0E ]
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johnhess··on Google Web Designer
As an engineer it's interesting to be on the receiving end of software replacing a bit of what you do. I suppose the market will always incentivize replacing expensive labor (high wages for developers cut both ways).

Granted, there have long been wysiwyg editors and this is a relatively simple part of the job of a web dev, but it's just another example of software eating the world.

johnhess··on Google is joining the Open edX platform
There are. edX has an authoring tool called Studio. It's part of their open source platform, usually hosted right alongside their LMS, and pretty straightforward for non-technical users. Of course, the farther you go into building custom problem types (e.g. an autograder to run on student-submitted code), the harder it is to do things in that basic wysiwyg interface. Still, it's very powerful and opens up all the basics (video, text, simple questions) plus some very rich experiences like peer and ML grading.

The original courses that edX hosted were authored in a rather tricky XML format. Authoring and QA in that system was time consuming for developers and borderline impossible for non-technical users.

johnhess··on The anatomy of the perfect technical interview from a former Amazon VP
I'm always amazed by how confidently people can propose a hiring "rule" or even guideline.

The article pays lip service to the fact "There's no way to A/B test hiring decisions" but then goes on to describe a handful of rules to "build an effective organization, regardless of size or resources." The thing is, there's no evidence that these are effective and definitely none to suggest they're generalizable to organizations of every size. There's an appeal to the author's authority as an Amazon VP (admittedly a hell of a credential), but that's not evidence of effectiveness.

The fact is, hiring is tough to learn. It's made especially difficult because your feedback comes at least 6 months after you make the decision. I've had the good fortune to be in an organization which grew from ~10 employees this time last year to ~80 now, so I've gotten to see how a few dozen hires panned out in a short period of time. I learned a lot through that. Even so, as a professional data geek, I couldn't say with a straight face that I "know" anything about hiring. I do my best day in and day out, but saying you've got hiring all figured out is the professional equivalent of knowing "What (wo)men want." It's a sign of confidence, but not necessarily knowledge.

Don't get me wrong, in the absence of quality data, I'll take the wise words of someone who has been there and done that. But I'd much rather some empirical proof or at least some "YMMV" humility from those who purport to know.

johnhess··on Iranian Hackers Post Images Over JFK Airport From UAV That Was Hijacked In March
What kind of list did I just get myself on for that little visit?
johnhess··on How well does Khan Academy teach?
The PC wasn't better than the mainframe at everything. It didn't have to be. That's how disruption works.

Many good instructors can't draw a line between KA (or any other disruptive solution) and the absolute best, gold standard, scientifically-proven best way to teach (usually their favorite methodology).

The fact is that he's better than most of the teachers out there. It's a rising tide: if your teacher has a Presidential Award for Excellence in Mathematics and Science Teaching you probably don't need Sal Khan.

johnhess··on If malware authors ever learn how to spell we're all screwed
My bank used to do this, and I never quite understood why. An attacker could easily mimic the site's behavior.

1. Attacker prompts me (or my grandmother) for login name. 2. Attacker gives login name to bank. 3. Bank serves proper image to attacker. Attacker stores image. 4. Profit.

johnhess··on US Navy's High-Resolution Radar Can See Individual Raindrops In a Storm
Seeing stealth aircraft isn't about resolution. The key to seeing something with radar is signal-to-noise ratio. From the article:

"it becomes possible to measure the properties of individual raindrops greater than 0.5mm in diameter due to the low concentration of such drops in naturally occurring cloud systems and the overwhelming dominance such drops have on the measured radar reflectivity when present in a field comprised of smaller particles."

It's easy to distinguish an airplane from something with a similar sized signature, say an insect, since the airplane moves at 1000knots instead of 1, but you have to be able to see it through the noise. That's tricky. If you use a radar like this (high power, really narrow beam) you might be able to see a stealth plane. But, you'd have to know where to point it. Therein lies the challenge.

johnhess··on A day in the life of a startup founder
10:45 put on a shirt (but not pants) for skype video chat with client.
johnhess··on Meet the ‘worst’ 8th grade math teacher in NYC
I don't think that's a debunking. yummyfajitas covered the plotting tool, but that's only the start.

Clearly, the metric is far from perfect -- you can tell that without his analysis. Year-over-year variation is high, indicating that there's likely a lot of noise in the measure. That said, year-to-year scores do correlate. This means that the measure is at least a little bit reliable in the sense that if you measure the same thing twice you'll get an answer that's close to the original.

All he's shown is that these are "noisy". There's no reason not to use a noisy metric, you just need to know that's what you've got, and make responsible decisions.

For example, don't fire teachers who rank poorly, but do review their performance. In that case, we'd find that the "Worst Teacher" is underperforming on this metric because it wasn't designed to test great students, and we can move on. Another example of the same phenomena in education is looking for teachers who help students cheat exams. When there are suspicious correlations found, administrators investigate.

One last thing: What he doesn't investigate -- and this is much more important -- is the (lack of a) correlation between value added ratings and other metrics (say, peer evaluations).

johnhess··on Thank HN: Claim your personal Screenleap handle until April 30
try to find a more obvious thing than the little "inactive plugin" at the bottom... just ignore "click enable" stuff these days, and wait for prompts (like up near the address bar).

hit people upside the face with it

johnhess··on MIT CSAIL PhD vs. Promising Startup
It depends on what you're into and exactly what you think your prospects are for each. I'm graduating from a different MIT program in June (SM 16/SM TPP), and I absolutely loved it here. If your experience is anything like mine, you'll meet tons of brilliant, awesome folks (that means you'll always be able to step out into the startup world).

YMMV.

Also, vonsydov had a good idea. I know a lot of MIT programs let you take a 1 year deferment. Maybe you can take a cut at the startup, and if you go belly up, go to school. If you end up a billionaire, buy vonsydov a beer.

johnhess··on Why Top Talent Leaves
"what do you aspire to bring to the world?"

Yes. Yes. Yes. One thousand times, yes. If you're asking me to dedicate my waking hours to something, be clear about what that something is. Hint: It's not your corporation.

I've interviewed at several companies, and the only ones I rejected out of hand are the ones that are just "doing business" and have ceased to chase some vision.

Some companies do really cool stuff, but have no vision (e.g. most of Lockheed Martin) whereas there are companies who do something seemingly less exciting (e.g. Yelp) that have a vision for how they're going to change the world.

In Yelp's case, they're helping great businesses thrive and be found and holding bad companies accountable. As an Aero guy, I'd be predisposed to Lockheed, but frankly, when I talked to Yelp, that kind of thinking made all the difference.

johnhess··on Indeed's stats show people look for jobs in new year - oldschool infographic
Looks like it might not be a new-year effect. A lot of search terms decline over the holidays.

If you ignore the dip, it looks like it might be nothing at all or just a "backlog" of would-be searchers from Christmas.

johnhess··on Ask HN: How to learn Data Analysis?
http://blog.stephenwolfram.com/2012/03/the-personal-analytic...

This is on the front page now, but holy crap is it beautiful. This is everything data analysis should be.

johnhess··on Ask HN: How to learn Data Analysis?
You're fluent with regressions and stats. Sounds like you're competent with the mechanics. Where you might have gaps, there are some great tools that can do your heavy lifting. But, that's only half of the battle.

When you're trying to do meaningful data analysis, you really have to understand your dataset. Fancy math can't substitute for domain expertise. Think long and hard about what's in the set, what the causal connections might be, and how an "expert" in the field might approach the problem.

The guys over at OKCupid are awesome at this. Check out this post to see what I'm talking about.

http://blog.okcupid.com/index.php/dont-be-ugly-by-accident/

Their advice on taking a good picture is just about exactly what my professional photographer mother recommends. Good stuff. But, the way they analyzed and presented the data shows (a) exactly how powerful putting numbers on something subjective can be and (b) that they know their domain.

If you read through the other posts (do that), you'll see that they have a solid understanding of their dataset. They know what to look for, namely photo attractiveness. They know how to get good data on that (the dependent variable) and they know which independent variables probably matter the most.

Throwing math at a complex dataset can be useful (e.g. bayes spam classifiers), but if you really want to do something that will work well or "speak" to a client, invest a bit of time in understanding the field.

johnhess··on MIT Techtalks saturday - TED speakers, MacArthur fellows and more.
Anybody know how big the MIT population on HN is? SWAG (stupid wild ass guesses) welcome.
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