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How Big a Sample Set?
You can project the behavior of your entire target market off a surprisingly small panel (what we call a “Micro-Panel”) of users equipped with the Intensity application, whereby what we call the TickStream™ is measured.

This is exactly what political pollsters do -- they ask a group of people a list of questions and based on the results, they draw conclusions about the population as a whole with those often heard disclaimers of "plus-or-minus 5%."

If you’re simply looking at one large group of people as a whole, the process of determining a random sample is very straightforward. You will need to know how many people are in the entire group (your target market) and how accurate you want your results to be, which is called "Statistical Confidence." For example, if you aim for 90% confidence with an error of 4%, you are saying that if you were to conduct the same survey 100 times, the results would be within +/- 4% of the first time you ran the survey 90 times out of 100.

If you are not sure what sort of error you can tolerate and what level of confidence you need, a good rule of thumb is to aim for 95% confidence with a 5% error level.

Say that you serve 10,000 doctors in total, and regarding researching their computer activity, you’re willing to tolerate an error rate of plus-or-minus 5%.

Further, you want to know what Micro-Panel size you need to be 90%, 95% or 99% confident in your results.

Thus, your panel size needs to be as follows, per confidence level:

  • 90% confidence: You need 265 doctors to download and install the Intensity app.
  • 95% confidence: You need 370 doctors to download and install the Intensity app.
  • 99% confidence: You need 622 doctors to download and install the Intensity app.
Say you could only live with +/- 3% as your error rate— then for 95% confidence, you’d need a far bigger panel than 370 doctors, one totaling 964 doctors. Here are the needed sample sizes, then, for target markets (“populations”) of from 10,000 to 100 million users, at the plus-or-minus 5% error rate level. By sample size, we mean how many users you need to get to download and install the Intensity app on their Windows PC or laptop, to form your Micro-Panel. You’ll see that as you get to very large populations, the needed sample set size does not change much, if at all.

Population Size 90%
confident
95%
confident
99%
confident
10,000 265 370 622
100,000 272 383 659
1,000,000 272 384 663
10,000,000 272 384 664
100,000,000 272 384 664

What if your market were all 300 million Americans, and you could only stomach a 3% error rate?

Then your Micro-Panel needs to be 756 to 1,843 users, as follows:

  • 90% confidence: You need 756 users to download and install the Intensity app.
  • 95% confidence: You need 1,067 users to download and install the Intensity app.
  • 99% confidence: You need 1,843 users to download and install the Intensity app.
Here’s a calculator on the web that makes determining your sample size very easy. Random Sample Calculator

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