The Cost
Two instruments for translating the documented margin into household terms.
Two instruments. Both are derived only from Tier A figures, both disclose their interpolation share, and neither produces an estimate of theft. What they produce is the documented margin: the arithmetic difference between the two published prices, applied to the volume the Central Bank published.
Exhibit A · Family exposure
Days lived under the window era, and the documented margin attributable per person over those days
For each day in the series with a recovered volume and both an official and a parallel rate, the documented margin for that day is the volume sold multiplied by the premium: volume × (parallel − official) ÷ official.
The daily margin is divided by the population of Iraq in that year to give a per-capita daily figure.
For each household member, the per-capita daily figures are summed across the days between their birth date (or 1 January 2004, whichever is later) and the end of the series.
Population figures are the World Bank mid-year series; the calculation states its interpolation share and omits any day for which either rate is unavailable.
Population series: World Bank, Iraq, mid-year estimates.
Exhibit B · Period reckoner
Any date range within the series
Documented margin is an arithmetic quantity, not an allegation. It states what the difference between the two published prices amounts to over the volume the Central Bank published in the selected period.
Source: Central Bank of Iraq, session bulletins Tier A