Page 41 of the referenced study/document does claim that, per its projections/algorithms, Sweden's HDI will drop, from 0.949 to 0.906 (e.g. to 45th place).
45th place is relatively low-ish (for comparison, currently Portugal is in about 45th place) but not "third world" ... the absolute HDI is still above 0.9 ... part of the reason why it's projected to be relatively low is that HDI of other countries are expected to rise.
My initial answer was as follows:
The document talks about how it calculates but doesn't explain it well/clearly enough for me to understand.
The document doesn't include the actual calculations for Sweden, only the result of the calculations.
However I think I understand it now, as follows.
The start of the document says,
The model was developed by creating “cohorts” of countries and then by
applying demography’s hypothetical cohort approach to observed 1970-2005 country-level
changes in HDI.
Looking at the brown lines (cohort 4) on page 45, one of those is downward: I presume that's Sweden; that Sweden's HDI dropped just before the study period; and that Sweden is the only country in its cohort whose HDI dropped.
Because Sweden's HDI dropped, the projection is for it to keep on dropping.
Because other countries were rising in the 2005-2010 period, their HDIs are projected to keep on rising.
Sweden's HDI continuing to drop for 20 years (projected from 2010 through 2030) contrasted with other country's HDI rising for 20 year, is enough to drop Sweden's HDI to 45th place.
- Yes it says 45th place
- No that's not 3rd-world
- It's a naive estimate, based on the assumption that because Sweden's HDI dropped recently it will continue to drop for the next 20 years, and that because other countries rose recently they will continue to rise for the next 20 years.
Even according to the report, even if you accept the report, Sweden is not "dropping fast": it's dropping a little. Dropping even "just a little" adds up if it's projected over 20 years; and looks relatively worse when almost all other countries are rising. But above 0.9 is still good in absolute terms: it's not "deteriorating fast", it's more like going from "top of the high HDI group" to "middle of the high HDI group", with the number of countries in the "high HDI group" increasing.
Perhaps more importantly, the purpose of the paper (for which the paper's methods of projecting was chosen) was to look at the HDI progression of cohorts (i.e. groups of similar countries), not of individual countries.
In fact the whole paper might be a red herring, in that according to footnote 8 on page 29, the document references the following for its 2030 projections:
8 Daponte, B. Osborne and Hu, Difei. “Technical Note on Re-Calculating the HDI Using Projections of
Components of the HDI.” April 2010. UNDP/Human Development Report Office.
My guess is that this is the paper which would explain why Sweden's HDI was, uniquely, calculated as dropping; but I haven't found a copy of this document so I can't review it. But even without knowing how Sweden's drop in HDI was calculated, there enough information (explained in this answer) to see how little this alleged drop matters.
A different more recent document i.e.
HDI values and rank changes in the 2013 Human Development Report shows that Sweden's HDI is currently rising (and has always been rising, never falling).
This document also says,
The rank of Sweden’s HDI for 2011 based on data available in 2012 and methods used in 2012 was 7
out of 187 countries. In the 2011 HDR, Sweden was ranked 10 out of 187 countries. However, it is
misleading to compare values and rankings with those of previously published reports, because the
underlying data and methods have changed.
In summary I don't think that the "Hypothetical Cohort Model of
Human Development" document is a reliable predictor of bad HDI for Sweden.