[bandushrew]

"I challenge anyone to point to any result in the study and give a reasonable explanation why that result is likely way off."

plan to buy: forrester 3.8% plan to buy: you 2.0%

so your results differ markedly from the forrester report itself?

Your results are different (and likely differ from reality) because you did not use a random sample, you used a self selected sample of people who belong to facebook and wanted to respond to a poll. That is simply a fact.

Having taken a non-random sample you then projected your own opinions into all your conclusions. Its an amusing post, but not really an interesting one.

[mytype]

There's two explanations for that difference:

1) Forrestor's 3.8% was collected in June 2010, whereas our data was collected from March through May. Clearly the iPad is gaining momentum, as time goes on more people are planning to buy one (at least for now).

2) More importantly, Forrestor said that "no time frame was specified in the survey question". So they asked people who don't own an iPad if they intend to buy one. That's fairly different from our question, which allowed the respondent to choose from:

1) plan to buy one 2) want to play with one first 3) will wait for later versions 4) waiting for the consensus opinion

Clearly, with the variety of options, some people who might have simply answered "yes" to the "intend to buy" Forrestor question would pick 2, 3 or 4 in our question.

Does that settle that? And by the way, these are people who wanted to take a personality quiz, not answer a poll. Their motivation had nothing to do with the iPad, that question was randomly inserted into the personality quiz.

While you seem to be "amused" by a blogger who in your mind completely makes stuff up, I'm amused by a commenter who after 5 minutes of review feels confident enough to slam a study that took multiple people dozens of hours to complete.

We're not publishing this in a science journal. That's not what we're going for. It's not complete BS either though. We do normalization, we have lots of data, and our psychological measures are based on the best contemporary research. The results are worthwhile. I'll say again: I challenge anyone to point out a major flaw in our data (not my interpretation of it).

[bandushrew]

So, in summary, you asked different questions during a different time period and came up with different responses, but still feel happy claiming that the forrestor report somehow validates your own results? why?

"these are people who wanted to take a personality quiz"

that is exactly my point. what subset of iPad users want to take a personality quiz? there is a clear self-selection bias there that you are, for some reason I dont understand, entirely ignoring.

"I'm amused by a commenter who after 5 minutes of review feels confident enough to slam a study that took multiple people dozens of hours to complete"

mytype, Im not slamming it, its amusing, Im just pointing out the obvious. its not science you were engaged in, its opinionated blogging. Your blog post would have lost nothing if you had just skipped the dozens of hours work to implement the poll.

Its not a useful poll in any sense of the word.

Its a non-random poll of self-selected facebook users and gives your post about the same degree of additional validity as the personal anecdote below regarding the people I know who own iPads gives my posting.

"It's not complete BS either though"

in what sense of the word?

from a scientific POV it is a poll from a totally non-random sample with entirely unreliable results, into which you manage to project conclusions that happen to suit you.

That is not intended as a slam, it is simply a fact.

If you are unhappy with that fact, you should try harder next time to use a decent user sample.

or phrase things differently. Although the poll doesn't talk about iPad users as a group; not even close; it does give a clear result of what a subset of iPad owners, who belong to facebook and chose to take a personality quiz, might be intending.

[mytype]

Yes, it's a biased sample. I've already admitted that. My point is that it's not egregiously more biased than any other sample from academia or professional surveyors, and in many cases it's less biased.

Do you reject most academic psychology research because it is based on students at the college of the researcher? Certainly that's a more biased sample.

Do you reject political polls because they're based on who answers calls from random phone numbers and then does not hang up once they realize it's a poller?

Do you reject most commercial research based on paid volunteers or visitors to sites with much smaller and more biased audiences than Facebook?

I state upfront in the article that this is based on MyType users who are on Facebook. What more do you want? If you want no bias, just do math and don't believe any data based on people, written by people, spoken by people, anything having to do with people.

The bottom line point is, this is much more rigorous than much of the crap blogs and media report on. I'll take a random example that I googled for the iPad: http://techcrunch.com/2010/04/06/ipad-sentiment-analysis/. "87% of tweets indicate intent to purchase the iPad". Give me a break. Talk about bias. The sampling errors there are horrific.

I'm just trying to maintain a reasonable perspective on MyType's data, not hide any facts about the shortcomings of it. There are shortcomings, they're just not so bad to make the results "entirely unreliable".

[bandushrew]

"87% of tweets indicate intent to purchase the iPad"

oddly enough, I have less of a problem with that article than I do with your post.

They clearly acknowledge all the limitations of the data right up front.

I can read that article and understand within the first 2-3 sentences that they are playing a game of mental masturbation, and then grin at the conclusions.

Its clearly a pointless piece of puff, and perfectly enjoyable as such.

My problem with your blog post arises because it is inviting me to take it more seriously than that.

You state upfront that it is based on MyType users who are on Facebook and who participated in a personality quiz.

The question you never speak to, and need to answer, is why on earth do you believe that a narrow sample like that can reasonably be used to draw conclusions about the broader set of iPad users?

do you fully intend that the blog post be a pointless piece of puffery similar to the techcrunch article? in that case, make that explicit.

do you actually believe that you can, using the statistics you have available, speak usefully about the broader set of iPad owners? explain why, giving your confidence level and other assumptions you have made.

If you want me to take it seriously, you need to take it seriously.

[bandushrew]

Bias in sample data is unavoidable, but the bias should be clearly called out before, during and after the conclusions to ensure that the context is not missed.

and yes, I do reject any poll that does not take the idea of sample context and data bias seriously, regardless of its source.

If you do not clearly acknowledge the limitations of the data you have, you might just as well spend your time making numbers up.

[bandushrew]

"I challenge anyone to point out a major flaw in our data"

its based on a non-random set of self selected participants who happen to use facebook.

That is a major flaw in your data.

Its useless to draw conclusions from it, unless you are specifically interested in drawing conclusions about iPad users who have a facebook account and like to fill in personality quizzes.

Having said that, if that small subgroup of iPad users is, in fact, the group that you wish to discuss then go for it, but please be clear about that at the top of your post.