Appendix B to Subpart C of Part 170 - Population Adjustment Factor

1. The Population Adjustment Factor allows for participation in the IRR Program by all tribes. This component of the funding formula creates a special calculation of funding which is available in accordance with the TTAM each fiscal year for a tribe based on the population range within which the tribe is included. The following table shows how BIA develops the PAF.

Population range	Distribution factor*	Number of tribes**	Funding amount per tribe
Less than 25	1	N1	MBA*** × 1
25-100	3.5	N2	MBA × 3.5
101-1000	5.0	N3	MBA × 5.0
1001-10,000	6.5	N4	MBA × 6.5
10,001 +	8	N5	MBA × 8

*Multiplier used to determine the PAF funding for the population ranges. For example, if $1000 is available for the first population range (less than 25), then the second population range (25-100) will receive $3,500 or 3.5 times the amount available to the first population range.

**The number of tribes changes yearly.

***The Minimum Base Allocation (MBA) is the dollar value to be multiplied by the distribution factor for each population range to determine the distribution of the PAF.

2. The following example shows how the PAF applies to a total IRR Program authorization for the allocation year of $375 million. The five steps to calculate the Population Adjustment Factor are applied as follows:

Step 1. For each population range, multiply the Distribution Factor by the total number of tribes identified in the population range to determine the Step Factor;

Step 2. Add the Step Factors determined in Step 1 above to derive a Total Step Factor;

Step 3. Calculate the $A = IRR Program authorization available in the allocation year by taking the Total IRR Program authorization for the allocation year ($375M for this example) minus the appropriate statutory and regulatory set-asides, as well as other takedowns ($25M for this example)

$375M−$25M = $350M;

Step 4. Derive a Minimum Base Allocation by taking 121⁄2 per cent of the difference (from Step 3) and dividing it by the Total Step Factor. The mathematical equation for the Base Allocation is as follows:

View or download PDF

MBA = Minimum Base Allocation

Distribution Factors = 1, 3.5, 5, 6.5, and 8

$A = IRR Program Authorization Available in the Allocation Year

$275M = Base Reference Amount

n = The nth Population Range

1 .  .  . 5 = Population Ranges 1 through 5

Nn = Number of tribes in the nth Population Range

View or download PDF

Step 5. Calculate Population Adjustment Factor within each Population Range by multiplying the Distribution Factor for the Population Range by the Minimum Base Allocation.

The mathematical equation for the Population Adjustment Factor calculation is as follows:

PAFn = DFn X MBA

PAF = Population Adjustment Factor

DF = Distribution Factor

n = The nth Population Range

MBA = Minimum Base Allocation

For example, for DF1 = 1.00; PAF1 = 1 × $3,215.57 = $3,215.57

For example, for DF3 = 5.00; PAF3 = 5 × $3,215.57 = $16,077.86

The following table illustrates the results of the above calculations for all population ranges:

Population range (step)	# of tribes	Distribution factor	Step factor	Tribal PAF per population range	Total funding per step
Less than 25	17	1	17	$3,215.57	$54,664.72
25-100	66	3.5	231	11,254.50	742,797.12
101-1000	309	5	1545	16,077.36	4,968,058.65
1001-10,000	137	6.5	890.50	20,901.22	2,863,466.82
10,001 +	29	8	232	25,724.58	746,012.69
Totals		Total Step Factor = 2,915.50			9,375,000