Sheet One

Type 1 in A2, 2 in A3. Select both. Mouse over to get the autofill cursor. Drag down to A11.
Type 2 in B2, 4 in B3. As above.
Type "Part 1" in C2, "Part 2" in C3. As above.
Type 9:00:00 in D2, 9:00:15 in D3. As above.

An aside on time values in Excel. Change format of D2 to Date. Change format to general. What does 0.375 mean? In cell E2 type the formula =9/24

Change the format back to Time. Note the default includes AM. Go to custom format, time, and look at the options.Then we go to Custom. [$-F400]h:mm:ss AM/PM The [$-F400] is an "escape sequence"

The underlying number is called a "serial date" and it's an integer representing the number of days since January 1, 1900. There are a whole bunch of functions in excel that you can use with date/time data.

Break Even

From Zero to Peer Effects Models in an Hour or so

  1. Iteration 1
    1. Resize rows and columns
    2. Merge cells
    3. Fill and border
  2. Iteration 2
    1. =RAND() function
    2. =INT() function
    3. How to generate random integers in some range
    4. Recalculate
    5. Paste Special > Value
  3. Iteration 3
    1. Conditional formatting
    2. Paste Special > Formats
  4. Iteration 4
    1. Add a spinner
    2. =COUNTIF(range,"<="&AB4)

A Simple Peer Effects Model

Let's assume that people adopt products in part because they see or hear about other people adopting products. How can we think about this?

One approach would be to assume that everyone knows how many people have adopted the product but that each person has a different threshold in terms of what number of other people using the product would cause them to "get on the bandwagon."

Some people are early adopters and will try a new thing out even though nobody else has it. Other people are very late adopters and won't try something until almost everyone else already has. And lots of people are in between.

Let's imagine a world with 100 people in it and let's imagine that each has a threshold between 0 and 1. If the fraction of the population using a product is at or above your threshold, you will adopt.