Intertemporal versus interspatial comparison
The following table examines intertemporal versus interspatial comparison in PPP calculation/index number theory. In particular, aspects of intertemporal comparisons have counterparts in interspatial comparisons, so the table catalogs these.
|How well the weights match the thing being compared:19||Up-to-dateness||Characteristicity|
|Tendency of Paasche quantity indices to be lower than Laspeyres indices:75||Gerschenkron effect||Own-weight effect|
|Ordering||Natural ordering by year (or other granularity of time periods)||No natural ordering (but some have devised orderings, e.g. an approach where structurally similar countries are compared to each other):32|
|The thing against which other things are compared||Base year||Numéraire country|
|Symmetry in treatment of the base||Time-reversal test||Country reversal test (bilateral) or base-country invariance (multilateral):71–72|
- Drechsler, László (March 1973). "Weighting of index numbers in multilateral international comparisons". Review of income and wealth. Retrieved November 12, 2017.
- Kravis, Irving B.; Heston, Alan; Summers, Robert (1982). "World Product and Income: International Comparisons of Real Gross Product (United Nations International Comparison Project Phase III)" (PDF). Johns Hopkins University Press. Retrieved November 5, 2017.