| Population Estimate - Methodology used in the PopClock |
Brazilian Population
Methodological Note:The monthly populational projections, with reference date on the first day of each month, were initially obtained through a geometrical adjustment to the values projected by the demographic components method which cover the period 1989-2012. The adjusting function has the following analytic expression:
POP (t) = A * t B
where:
t = reference date => 01/07/t,
POP(t) = Population projected for date t,
A and B are parameters to be determined,
The parameters resulted in: A = 190,250 and B = 1.4756, with R² = 0.9999 through the method of minimum square estimates.
With the determined function, it was possible to monthly interpolate the population projected between the respective years.
The average rates of monthly populational growth were reduced to the scale of minutes using the expression D*H*M as a time variable, where D = number of days per month, H = number of hours per day and M = number of minutes per hour. These rates were used to obtain the populational estimates at each minute.
World Population
World population estimates are presented in table 1 (Total Midyear Population for the World, 1950-2050) of the International Database of the U.S. Bureau of the Census. That table shows the estimates of world population from 1950 to 2050. For each year estimates are presented for the 1st of July at 00:00 GMT. For the world population estimates presented by IBGE PopClock minute by minute interpolations were made between the estimates for each one of those years.
The IDB-International Database of the U.S. Bureau of the Census is based on the available analyses of census data and fertility, mortality and migration surveys. The analysis is made separately for each one of the 227 countries or areas of the world with population of 5,000 inhabitants and over. Diverse statistical tables of demographic and socioeconomic data are available on that database.