The Australian Bureau of Statistics is about to dramatically intervene in the debate over the life expectancy gap between indigenous and non-indigenous Australians by unveiling new data showing indigenous life expectancy is significantly higher than previously calculated.

The new data is the product of a year’s research into ways to address under-reporting of the deaths of indigenous people but is likely to lead to claims the Government is manipulating data to suit its “Closing the Gap” agenda.

The ABS decided not to publish indigenous life expectancy data from 2007 last year as it grappled with addressing the problem of accurately counting indigenous deaths. Previously, it was estimated that the gap between indigenous life expectancy and that of the overall population was about 17 years. Life expectancy for all Australian children born in 2005 is now 79 years for boys and nearly 84 years for girls.

The ABS’s previous method would, if applied based on current data, yield indigenous life expectancy of 61.7 years for boys and 69.3 for girls. This “indirect” method tried to identify the extent of under-reporting of indigenous deaths, which is a critical impediment to estimating life expectancy among indigenous communities and primarily a consequence of non-reporting of a deceased person’s indigenous status by people filling out death registration forms. The method tries to compare how a population changes between censuses and how that matches with registered deaths.

The method has developed through several iterations in recent decades but is heavily dependent on assumptions about issues like migration and census coverage. Changes in assumptions can yield two or three years’ difference in life expectancy results. One version had Northern Territory indigenous males suffering a near six year fall in life expectancy to below 52 years between 2001 and 2006, while NSW indigenous male life expectancy rose more than seven years.

In November the ABS produced a discussion paper proposing a new, more direct method that used the fact that the ABS had conducted an additional indigenous mortality study after the 2006 Census that enabled it to better understand the extent of under-reporting of indigenous deaths. This will allow the ABS to better adjust its figures to account for under-reporting.

The result it likely to be a dramatic increase in indigenous life expectancy — the discussion paper suggests just under 67 for boys and 72.6 for girls.

The ABS, which says it has received overwhelmingly positive feedback on the discussion paper, will release details of its decision on the methodology it will adopt on Monday morning, including the results of its new calculations of indigenous life expectancy, which is likely to be more like a 12-year gap than a 17-year gap.

The ABS will heavily caveat the material to warn that the new figures cannot be compared to previous data. Inevitably, however, the abrupt narrowing of the life expectancy gap will be interpreted as a Government attempt to claim big progress in addressing indigenous health.