Class:
Informatics, Computing, and the Future
Instructor:
Dan Berleant
Transcriber:
Brooke Yu
Date:
Thursday, January 31, 2013
Professor: Okay, so what I thought we'd do today is finish
up on the Delphi method so everyone could have a chance to gather some
data. You'll use that for some homework
soon. There are a few people left to do
that, then I have to answer some questions about the homework, and then we'll
start on the next topic, which is prediction markets- another way to predict
the future.
Why don't we
start with the homework?
I know a
couple of people sent me emails about how to do it. Anybody can explain what their question
was?
Does everyone
know how to do the homework? I got
emails.
Male
Student: I'm not sure where to
start.
Professor: Okay, let's see. Where to start. I guess I could say start on question 1, and
that's probably where you're having trouble.
Remember we
talked about exponential curves and how they start kind of slow and then speed
up? It turns out that exponential
curves.... it either speeds up or slows down, depending on the sign.
The homework
was about, to give you practice playing with that concept of exponential
change.
Exponential
change, you know.... it's sort of a general formula is something.
You know,
this should be t because we're talking about time. At some time, it's the amount of- the height
of the curve is 2 to the t or, maybe instead of 2 it's some constant, but an
exponential curve has a formula where it's some constant raised to an nth
power. When you raise something to a
power, it goes up really fast.
Like, 5
squared is 25, 5 cubed is 125, 5 to the 4th is... what's 5 to the 4th? It's 625, right? That's a pretty fast increase.
5 to the 5th
is like 625 times 5 which is 3125, and we're only up to 5. When we get to the 6th power, we're up to
15,000 plus. It's increasing at a faster
and faster rate.
If you were
to plot these, they'd be a stair-step, kind of, and each stop would be bigger
than the previous one.
So here, the
variable is the exponent. The exponent
in this case is time.
The question
is how do you apply this to the homework.
The questions
in the homework are, for example... you know, estimate the doubling time of
software development productity. [On
board.]
Every year,
the products available to computer programmers get better, so code is produced
more efficiently. Next year, people
should be able to produce software 6% more lines per day. So how long will it be until someone can
produce twice as many lines of code as they can now? Let's suppose people can produce 100 lines of
code in x hours.
You know,
fully de-bugged- commercial production code.
It doesn't matter how many hours it will take. The is year 1, by the way.
Okay, then we
have 3, 4, 5... [On board.] This is how
you do it.
I'd better
not say 6% here. Let's say 5%. In year 2, people can do 105 lines of code,
if it's 5% improvement. I'll type equal
sign, e1 *1.05.
Okay? You probably ought to know how to use a
spreadsheet. If you want to use a
calculator, you can use pencil and paper to add 5%.
So I'm going
to use the same formula. I'm just go to
copy, paste it in here... copy it again here, and if you look at the formula-
it's up here.
Let me double
click it. Every time I paste it it
translates the formula to be suitable for the new cell.
Here, it's
this is the previous box times 5%.
I'll keep
pasting these... [On board.]
You can past
more than one at a time. I'll go like
that. You can see that, if you start in
year 1 at 100, you're up to 200 lines of code per unit of time somewhere
between year 15 and 16. So let's
estimate 15 years doubling time.
Okay? You can do it analytically, but this is
easier and works pretty well and gives you experimentally produced
results.
Okay? Do you want to try an example on a
spreadsheet? Ho many people want to try
an example?
Okay, here's
another example.
Let's suppose
cell phone batteries- the capacity of a cell phone batter decreases by 1% every
week. Let's say the battery starts out-
it lasts 150 hours before it needs to be re-charged. That's just if you don't use it.
And that's in
week 1 after you get the cell phone.
If it
decreases by 1% per week, that means in the second week its capacity will be
150 - 1%. What's the formula for 150
-1%?
Male
Student: The cell above times .99
Professor: Okay, yeah.
You could say the cell above it and just do 99% of that.
Okay, which
is actually about 148 something... there it is 148.5.
I'll do a
straightforward subtraction. We'll do
this, minus 1%, which is .01 times of the first cell, and I should get the same
answer. And this weeks. This is capacity of the battery.
How long will
it take for the battery to... let's suppose when the batter decreases to 10%
capacity of what it was when it was new, then you have to throw it out and get
another one. Let's just see when this
gets to be 10% of 150, which is 15.
That's not a half time or doubling time, it's a 90% decrease time.
So I'll just
paste a bunch here [On board.]
And I'm go
to, you know 3, 4, 5, 6, 7, week 7, 9, 10... I'm getting tired of typing, so
I'll do equals the previous week + 1.
I'll copy
this formula and paste it.
[On
board.]
It's a pretty
good battery. If it goes bad when it
gets to 10% of its original capacity, let's see how many weeks that is before
we get down to 15.
I'm just
pasting more numbers in.
Alright. So at week 230 it's 10% capacity and you have
to buy a new battery. That's 4.5 years
almost, so that's a pretty good battery.
Most cell phone batteries probably don't last 4 years. So any other questions?
So you can do
it for the homework problems now, right?
Okay.
Exponentials. Another way of saying- this turns out to be
the same thing as saying it decreases or increases by a certain percentage
every unit of time. Percentage per unit
of time- 10% every year, subtracts 1% every week- those are exponentials. You don't have to write the formulas
though. Just do it in the spreadsheet to
get the answers.
I undid
the... let's go back to the course website
So why don't
we finish the Delphi method for people who have not obtained data yet. Who has not gotten their data yet?
Okay,
you're... Zach.
Professor: Is Kurt here?
Male
Student: Yeah, but I went last
time.
Professor: Okay, we'll get to you in a minute,
Zach. Who else hasn't gone yet?
Female
Student: I haven't.
Professor: Were you her before?
Female
Student: No
Male Student: I think we got everybody else?
Professor: Is Wiliam Smith here?
Male
Student: I went the first day
Professor: Oh, okay.
And Andrew, you went. I think he
went, but he's not here anyway. Tanner?
Male
Student: I went.
Professor: How about the other Zach. Which Zach are you?
Male
Student: Lain.
Professor: That's right.
Is the other Zach here? No. Okay.
Professor: So we have two people to do the
exercise. Someone explain the delphi
method
Male Student: You poll opinions on questions.
Professor: What kind of opinions?
Female
Student: When it's going to happen.
Professor: So an opinion on when it will happen. When will we send the next spaceship to
venus? Some people might think it's in
2030. Others think will be sooner. People have opinions on the date. So you start by asking a question. What's the second thing we do in the delphi
method?
Female
Student: You poll the audience.
Professor: Alright, you get all the answers from the
audience. Remember, Delphi refers to an
oracle or something that gets you an answer.
You sort of treat the people as oracles.
So what's the third step. So we
find the median. If you get a bunch of
answers, it's helpful to find the middle one.
Why do we pick the median instead of the mean?
Female
Student: Because of outliers.
Professor: Right.
If one person says 2013, one says 2014, 2015, 2016, then someone says
2800, it doesn't seem to average them, because it adds 200 - 300 years to the
value. On the middle value is more
informative and useful than the mean.
Maybe this person picked 900 instead of 800 and it would change
everything. So we go with the median
because we felt it was a better way to kind of boil down the crowds
opinion. Mathematically, it's just as
good as anything else, but it seems more judicious in the opinion of people
like me.
There's no
law you have to do it that way. Can we
get anything else besides the median to distill the group's wisdom? Someone else?
Male
Student: You can discuss.
Professor: Alright, that's the next step. After you get the median then you
discuss. By asking people questions to
get their opinions, they haven't used each others wisdom yet. We discuss why people picked their answers. They learn more of the factors they may not
have thought about before. Maybe they'll
guess differently later. That's why we
discuss it. Discussing makes everyone
smarter and wiser for step 5 which is to get another set of answers.
Then what do
we do? How about step 6?
Male
Student: You get the median again.
Professor: Right. We find the median again. And you presumably have a better estimate now
than your you do before because people discussed it and have more wisdom than
before.
Okay, what
else might we take besides the median?
Somebody?
Anybody?
Male
Student: The average.
Professor: Yeah, we could take the average to give the
outliers some say. We didn't do that
before, but we could. I showed you a
graph on the board which .... I don't know what the shape is called. It kind of looks like this [On board.]
Remember? This was the median, this is time, and this
is the middle 50% of responses, then the 25% here is an outlier of this,
another 25% here might give an outlier like this. And this is the diagram. This is the total range of responses.
That kind of
sums up the spread or the range of responses.
Okay?
We haven't
done this in class because it takes too long, but for homework 3 you can
generate a graph like this for the data from your question.
Okay, so...
for those of you who haven't gone yet, I guess who are here, that's Zach and
lindsey- do you sort of get how the process works? Any questions? Well, the first thing you're going to need is
to think of a question that has a future time point associated with it that
you'd like to know about.
So let me
give you both a minute to do that.
Female
Student: I need an example of questions
other people asked.
Professor: Okay, let's go around. What was your question?
Female
Student: When will humans be able to
teleport.
Male
Student: When will holograms be made for
communication.
Male
Student: When will energy based weapons
be common place
Professor: Does that kind of give you an idea?
Female
Student: Yeah.
Professor: It can be anything you want.
Male
Student: So when will wires become
obsolete?
Professor: Okay, let's try it.
Professor: I hate wires.
You're always tripping over them.
So when will wires become obsolete?
Actually, one step we didn't mention was another step here- specify the
question optimally. You know, polish the
question. Does this question need to be
polished?
Male
Student: I mean, does it apply to all
wires?
Professor: Yeah, which wires?
Male
Student: Say, for industrial
networking.
Professor: So for computer networks?
Male
Student: Sure.
Professor: Okay when will wires become obsolete in
computer networks. Is this specific
enough? Do you mean networks within a
building or institution or do you mean trunk lines that send Internet
signals.
Male
Student: Just within a building.
Professor: Okay, by obsolete do you mean in the US or
everywhere?
Male
Student: Everywhere.
Professor: So you can see the process we're going
through- making the question clear and specific. Okay, well let's take- I'll give you a minute
to think of a date for this and then we'll do the process we've been
doing.
Male
Student: Over the course of changing
answers, does the question change or do you just modify your answers based on
the general discussion.
Professor: People will modify their answers based on the
discussion.
Professor: Okay, so let's do what we did before. This time let's start at this end of the
classroom. Just call out the years.
Female
Student: 2018
Female
Student: I say never.
Female
Student: 2030
Male
Student: I also say never.
Male
Student: 3000
Female
Student: 2100
Male
Student: 2045
Male
Student: 2045
Male
Student: 2045
Male
Student: 2030
Female
Student: 2030
Male
Student: 2038
Professor: Okay.
At this point, we need a recorder, because you're going to be using this
data for one of the homeworks. You'll
analyze it the way we looked at it here.
Not the one that's due this week.
We need a recorder to write this data down for Zacharay. Can you do it?
Male
Student: Should I email it after?
Professor: Yeah, or you can write it on a piece of
paper. Let's go ahead and find the
median. So we'll start by crossing out
the biggest and smallest numbers to converge in the middle. [Teacher reading: [On board.]
The middle
one is 2045. Okay? That's the median. And when you graph it, 2045 would be right
here.
Male Student: What does the question is?
Professor: When will wires become obsolete everywhere in
computer networks in a building.
Male
Student: Okay.
Professor: Okay.
So now we go to step 4, and we discuss why people picked the dates that
they picked, and we'll just sort of make everyone a little wiser and have more
to consider. So somebody- can someone
explain?
Professor: Okay.
Any other comments?
Male
Student: I say never because wires are
also kind of like a backup for whenever your wireless goes down. Generally you'll always have a backup. I mean, it might seem obsolete, but it's
there for backup.
Professor: Any other comments? Okay.
The process then after people have heard a couple of things they might
have not thought of. We give them more
time to think and then we'll ask again.
I'll give you another 45 seconds to think of your answer again.
Professor: Okay, so let's do the same process and see if
things will change.
Female
Student: 2030
Female
Student: I still say never.
Female
Student: 2030
Male
Student: Never
Male
Student: 2030
Female
Student: 2100
Male
Student: Never
Male
Student: 2045
Male
Student: Never.
Male
Student: 2030
Female
Student: 2030
Male
Student: Never.
Professor: Okay.
This is interesting. It
definitely changed, didn't it. Okay, we
had a bunch of highs this time. So it's
still the same. I mean the median is the
same, but the spread is different. It
looks to me like there's a skewing.
Female
Student: The average would be a lot
higher.
Professor: Right, well, we can't average infinity in
there. It's also interesting, as you
consider more things, you tend to change your estimate, which leads to an
interesting possible problem with Delphi methods. If one person has more charisma or argues
more strongly, that person can have an undue influence on the group's wisdom. Maybe they know more, or they're just more
convincing. So you know this is biased
because of the bandwagon effect. The
first poll is unbiased because there's no discussion. After, some people may be more convincing
than others. So these are someone
defects with the Delphi method. This may
weight opinions more than others.
Smarter, but not weighted fairly.
There are
some other problems with the Delphi method.
Let's see. There's a diagram that
I showed you there.
Okay, so
here's a few more items. If you were
doing it as a government agency trying to figure out where the economy is
going- you know, they want to support the right kind of scientific
research. If this was to be done
professionally, well, for one thing, it wouldn't take five minutes per
question. You'd be dealing with
experts. It might take days. And people might have a lot of arguments, so
it'd be longer and more details.
You can come
up with any variation you want, but typically you give a starting estimate,
then after discussion, give a closing estimate.
Here's an
article about it. Well, I guess they
took it down. Never mind. Some problems in the method - ambiguity of
the question. Maybe some people
understood the question differently.
That's possible.
Maybe someone
thought obsolete meant 90% of the buildings don't have it, and others might
think it meant 99% don't have it.
I'll give you
an example of ambiguity in English and how you can't get rid of it.
Male
Student: Maybe they're talking about more
than one dog?
Male
Student: Or they're all kept on one
leash.
Professor: Right.
Maybe someone might think the park provides one long leash. Any other ambiguities?
If this is
the rule, then if have to put the dog on a leash in your house. All
dogs, not necessarily in the park, have to be on a leash. Any other ambiguities? Kept permanently? During the open hours of the park? Does this mean all dogs have to have a leash
permanently attached? Maybe there are
some others as well.
What's a
dog? Do puppies count as dogs? Technically if you're a dog breeder, dog only
refers to male dogs.
Well, what if
we tried to fix the problem? We could
modify the rule. We could say dogs must
be kept on their own leashes. It's hard
to get id of the ambiguities, and the rule gets hard to read.
Male
Student: All canine species.
Professor: What if your dog is half wolf? That's a problem with the Delphi method in
general- ambiguity. I'm not saying you
can't come up with something, but it's hard work and it's difficult to do.
Are there any
other.... well, let's say we made the question perfectly precise, and the
people involved with the Delphi effort were experts. They spent decades working in the area. They're experts. We also make sure that when they discuss it,
nobody is campaigning. Everyone is
represented in the discussion evenly. Is
the result a correct result?
What do you
think?
Is the result
correct? If we do everything wrong, is
the result correct?
Male
Student: You have to wait and see.
Professor: Right.
You can't predict the future, so it's not a failsafe way to do it. Experts are often wrong.
Okay. We've got one more. So you get to ask a question now.
Female
Student: When will people live on the
moon?
Professor: Okay, recorder, have you got all this
down?
Male
Student: Yeah.
Professor: So can I erase it?
Male
Student: Yeah.
Professor: Okay, when will people live on the moon? Any ambiguities in the question?
Male
Student: Permanently or visiting?
Professor: Let's say the earth's moon. Okay, and is it temporary?
Female
Student: Permanently? I don't know.
Permanently.
Professor: Any other ambiguities to the question? Okay, well take a moment to figure out your
answer and we'll do the process.
Professor: Okay, let's poll the experts now. We need a recorder.
Female
Student: I'll do it.
Professor: Okay, just call it out.
Male
Student: 2050
Female
Student: 2050
Female
Student: 2050
Male
Student: 2050
Male
Student: 2051
Female
Student: 2035
Male
Student: 2045
Male
Student: 2045
Male
Student: 2400
Male
Student: 2050
Female
Student: 2040
Male
Student: 2050
Professor: Looks like the median is 2050. Okay, any comments on why people picked the
dates they picked?
Male
Student: I think if the Mars thing is
pretty successful, then they'll just want to go populate everywhere
Male Student: Our government is already trying to get back
to the moon. It's just a matter of time
once we get there what we do next. The
obvious choice is to settle.
Professor: Any other comments?
Male
Student: I think we'd prefer to live on
mars than the moon because there are more resources there.
Professor: When did they want to have colonized
mars?
Male
Student: I think 2028.
Professor: Did you apply?
Male
Student: They want me to describe why
I'd want to go to mars.
Male
Student: Why would we colonize on the
moon though other than if there's no place left to live on earth. What does the moon have to offer besides a
rough life?
Male
Student: Because we can.
Professor: It's real expensive. Someone has to pay for it
Male
Student: There's no resources that I'm
aware of that are crucial.
Male
Student: Also, I mean, government
funding has gone down significantly for things like that, but we see a lot of
private industries taking an interest in things like that. So I mean, as far as resources on the moon-
Male
Student: Unless you can figure out by
2045 how to make artificial atmospheres.
Professor: Alright, any final comments on this? Well, take a moment to think of your updated
estimate. We need a recorder.
Female
Student: Oh, I'm do it.
Professor: Okay, good.
Professor: Okay, this is before discussion. And just call them out.
Male
Student: 2018
Male
Student: 2200
Female
Student: 2100
Female
Student: 2050
Male
Student: 2050
Male
Student: 2200
Female
Student: 2080
Male
Student: 2050
Male
Student: 2050
Male
Student: 2400
Male
Student: 2050
Female
Student: 2040
Male
Student: 2050
Professor: Okay, let's see what happens.
[Teacher
reading: [On board.]
Professor: Looks like, despite the discussion, we have
the same median, but the numbers have changed a bit. So recorder, just get this data down so she
can analyze it
Male
Student: It could be a tourist
destination.
Male
Student: It could be like a gated
neighborhood.
Male
Student: You could just jump over the
gate!
Professor: Okay, so that's the Delphi method, but it's
not the only method.
Here's one
called prediction markets. You've heard
of the stock market, but this is where people buy and sell predictions.
Here, if you
say the wrong date, you don't have to worry about losing money. If you had to worry about losing money...
like if we put money on these dates... you'd think a little differently. The idea of prediction markets is for people
to put money on their predictions so that if they care about it, they'll do a
better job.
Can anyone
think of an everyday example of where people make predictions and put money on
them?
Male
Student: Horse racing
Male
Student: The super bowl.
Male
Student: Stock markets.
Professor: Right.
In my high school, people would put a few dollars on their favorite team
winning the next game. I mean this is
exactly like that. It's like a sports
betting scenario. Sometime people will
bet on the team because they like the team, but usually it's to be right. And to make money.
We don't have
time to go over all this today.
Sports, you
know, is this guy going to win the Wimbledon tournament. I don't know if he won or not. Let's look at an actual prediction
market.
This is a
company based in Ireland because it's not really allowed in the US because it's
like betting.
Although this
is a real prediction market, it has to be based off-shore. The company is called Intrade. The person who started the company- he
actually died climbing Mt. Everest.
That's a very dangerous thing to do, and he died on Mt Everest. Clearly a person who liked to do risky and
interesting things. One of them was to
climb Mt. Everest. The other was to
start a prediction market.
So what is a
prediction market?
People
betting to predict when something is going to happen- just like we did with the
Delphi method. If it happens you get
more money. If it doesn't happen, you
lose your money.
Ultimately,
the market will always produce a yes or no answer. The way it works- one of the bets might be
"a human being will land on the moon again by 2017." And by the end of 2017, those who bet yes
will get money if someone lands on the moon.
People who bet no will lose money in this case
At Intrade,
all questions are yes or no.
When do you
buy and sell? Although the answer is yes
or no, if you are to think about it now, you might not- many people might say
"maybe yes or no and give a percentage.
If the
average person thought it was 80% possible, then the share would sell for
$8.
You could buy
a prediction that they will or $8. And
if someone does land, you'd win $10, okay?
And if they don't land on the moon, you'd lose your money.
Every
prediction is ultimately either $10 or $0, depending on whether you guess right
or wrong. But how much you pay for a
share depends on what everyone is betting.
If it was $9 per share, but you only thought it had an 80% chance, you
wouldn't want to buy it.
Ultimately,
you either get $10 or you get $0, but what you pay depends on what people are
betting.
So who are
you buying from and selling to? Other
people who are trying to buy a prediction they think will be true for less
money.
Ultimately,
every prediction share is worth either $0 or $10 once the prediction is
determined to be true or false. So
what's your potential profit? If you buy
at a low price, you might gain $10.
What can you
lose? Maybe you buy it for near $10 but
it doesn't happen and you lose your $10.
Where do your
profits come from? Other people's
losses, really. It's like any kind of
sports betting. There's a pool of money,
and those who guess right get to split the money. Those who guess wrong lose their money.
How do you
cover your losses? If you really wanted
to use Intrade, you'd send them money and then buy shares.
Let's suppose
you buy a prediction share at $8. The
next day it's up to $9. You can
immediately share and gain $1.
Any questions
about how this works?
Want to look
at a couple of examples?
Professor: [Teacher reading: [On board.]
Anybody see
Argo? Do you think it's going to win an
academy award?
Male
Student: It was pretty good.
Professor: Here's what other people think. Some people think it's more likely or less
likely, but the average person thinks there is a 59% chance that it will. So you can go online now and by a share that
it will for $5.90. If it happens, you
get $10. If not, you lose $5.90.
You can see
that back in, not that long ago- about a week or two ago, it was down at
5%. When did you see the movie?
Male
Student: A couple days ago.
Professor: So you didn't really know. If you had seen it early on, maybe you would
bought a share when it was only 5%. You
could have bought a share for $0.50. Now
it's $6.
Let's look at
another one. We only have 6 minutes
left. Let's just look at a few.
UK economy
will go into a recession. Some of these
are important questions. You can even
look at future presidential elections.
Looks like democrats are a little ahead right now. Actually, it looks much closer.
There's a 47
to 48% chance for this. To be even, the
democratic is up a little more, so it's close to 50/50, which is what you would
expect.
What's the
chance there will be an obvious air strike against Iran by December 31st. If you think it's going to happen, you should
buy a share now while it's low.
This says
that the prediction market- crowd source wisdom, says there's a 25% chance
it'll happen, which is high for the question.
These are the
categories. Anyone want to pick
one?
Male
Student: Scientific.
Professor: Here's the most active ones- fusion process
to generate power.
[Teacher
reading: on. That one's covered up. What do you think this will?
Male Student:
1%
Male
Student: 80%.
Professor: Any other guesses?
Male
Student: 60%.
Professor: You have a fair amount of confidence we'll
find extraterrestrial life.
Male
Student: Are we talking about bacteria
or like that guy?
Professor: Well, the way it's stated it would include
bacteria.
Male
Student: Then I'll say 60%.
Professor: I'm not sure they'll find any by December
31st.
Professor: 3% chance.
Alright, your estimate is closer to the general opinion. For those who picked 70 or 80%, you should
buy now because if it's true, you'll get $10 at the end of the year.
They have a
lot of these.
These are the
most active.
There must be
a way to find all of them.
Male
Student: On the left under
scientific.
Professor: You can see that it's not when it's going to
happen the way the Delphi method works.
So 3% chance by the end of this year.
If you give it another year, let's see.
11.7%. So people there's a higher
chance if you give it another year. What
about by 2015? 19%. So I don't know how they did this. You know, you can see how people are trying
to sell right now. These are what people
are willing to buy or sell the shares for.
You put bids
in for those.
[On
board.]
Let's do one
more. Just a quick one. You've heard about global warming.
[Teacher
reading: [On board.]
Professor: What do you think?
80%?
Male
Student: 10%.
Let's
see. Alright, it's currently estimated
at 25% chance. By December, this will be
pretty close to accurate. Okay. So next time we'll talk more about prediction
markets.
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