Lag: I didn't mention this in my last post to you because the 9-Billion Milestone Year wasn't especially important to the discussion. However, the 5-Pt. regression I performed projected that 9-Billion Population would be reached in 2051, versus your Macro-Economic friend's estimate of 2050. I suspect he's using a somewhat similar but more complex methodology than I am, for I don't have a multi-regression software package anymore. Nevertheless, the resulting answers were very close.
I performed a few additional analyses aimed at finding the latest and greatest trends. I began with an assumption that if I narrowed the range of Milestone Years, performing 4 Pt. 3 Pt, and then 2-Pt. data, I might discover a continuing extension of the projected Milestone Years in which each Billion-Pop’ Milestone was reached. The analysis I performed earlier consisted of 5 Milestone-Year data points, those being the Year and World Population data for 1927, 1960, 1974, 1987, and 1999. The follow-up regressions I performed included only the 4 most-recent Milestone Years, then the 3 most-recent Milestone Years, and finally the 2 most-recent Milestone Years.
What I thought I’d find when I started was a consistent extension of each regression’s projection of the future Milestone Years in which the Billion-Population increases occur. I was surprised by what the outputs of each progression were. Here they are:
Regression
R2 = 95.7%100% 100% n/a
Milestone Year
Billion POP 5 Pts.4 Pts.3 Pts.2 Pts.
8 2035 2025 2025 2025
9 2051 2035 2035 2035
10 2068 2051 2051 2051
11 2085 2068 2068 2068
12 2102 2085 2085 2085
13 2118 2090 2090 2090
14 2135 2102 2102 2102
As you see, although I rounded the Years, the Billion-Pop’ Milestones for each regression occurred in the Year shown +/- months, and the 4, 3, and 2-Pt. regressions each projected the Same Milestone Years for the Billion-Pop’ Increases. Any thoughts???
