Visual comparison of income mountains on linear scale and log scale

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Updated by Ola Rosling on October 4, 2018

When visualizing income, we don't use a linear scale, because the value of one dollar is not the same on different income levels.

The value diminishes with higher incomes. Instead we use a doubling scale, or logarithmic scale, which makes doubling of incomes be the same distance, on all levels of income.

The data below are used to compare the look of the curves when using a linear, vs doubling scales.

These two graphs shows the same data but with different x-axis scales.

Comparing the number of people on different income levels in Mexico and USA.

Linear scale graph

Linear brackets

Log scale graph

Number of people in each income bracket ( $/day in constant ppp dollars 2011). The $ value at the top of each column, represents the upper limit of the bracket and the previous column is the lower limit. The brackets width increases exponentially, at a rate of 1.148698355 which gives a doubling within 5 brackets.

Exponentially increasing brackets

The number of people in each income bracket was calculated by based on estimates of Mean Houshold Income and a common assumption about lognormal distribution of people over income.

Documented here:

gapm.io/ddocincm

household_income