So, you’re lying quite a bit. And this is the picture that we’re talking about here. This is from the New York Times. Now, these are credible news sources doing this. And sometimes they do it deliberately, but more often than not they do it because they want to make it look pretty. They think to make it look pretty is more important than actually showing the truthful data.
How do you show data that is one-dimensional? How do people show that? Do they really show it fairly? This is a really common problem. What you’ll see a lot of times is data points tend to be one-dimensional data points. I’ve got a graph I’m looking at here. It’s the number of doctors devoted to family practice for different years.
In 1964, it was 27%, 1975 it was 16%, and 1990 it was 12%. Those are three numbers. Those are single points. Each number represents just a single dimension of data—just a point. But the graph I’m looking at represents each one of those points by a picture of a doctor—a nice little drawing of a doctor holding a clipboard.
And the problem with this is that these pictures are two-dimensional. So, what the picture is doing is it has the height of each doctor. It’s proportional to those numbers—27, 16, and 12. But the picture doesn’t just have height. The picture also has width and as you know the size of an object is proportional both to its size and its width.
And so, if you’re presenting one-dimensional data with a two-dimensional object the size of that object tends to be over-exaggerated as it gets larger because both the width and the height are both growing. And so, in this case here—27% and 12%--we’ve got a difference of what is that—about 100%? It a little bit more than doubled between 12-27%.
But these pictures—even though they’re twice as high, they’re actually about four times the size because when you double the height you also double the width. So, this is a lie factor of about four here because it’s representing 100% data increase with the 400% increase in size. That’s a really common problem.