2008 OASDI Trustees Report

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IV. ACTUARIAL ESTIMATES

IV. ACTUARIAL ESTIMATES
This chapter presents actuarial estimates of the future financial condition of the Social Security program. These estimates include projected income and cost of the OASI and DI Trust Funds, in dollars over the next 10 years and as a percentage of taxable payroll or in present-value dollars over the full 75‑year period, along with a discussion of a variety of measures of the ade­quacy of current program financing. In this report we carefully distinguish between (1) the cost (or obligations) of the program, which includes, for the future, all benefits scheduled under current law, and (2) expenditures (dis­bursements or outgo), which include actual payments for the past and only the portion of the cost of the program that is projected to be payable with the financing provisions in current law.
As described in the Overview section of this report, these estimates depend upon a broad set of demographic, economic, and programmatic factors. Since assumptions related to these factors are subject to uncertainty, the esti­mates presented in this section are prepared under three sets of assumptions, to show a range of possible outcomes. The intermediate set of assumptions, designated as alternative II, reflects the Trustees’ best estimate of future experience; the low cost alternative I is more optimistic and the high cost alternative III more pessimistic for the trust funds’ future financial outlook. The intermediate estimates are shown first in the tables in this report, fol­lowed by the low cost and high cost estimates. These sets of assumptions, along with actuarial methods used to produce the estimates, are described in chapter V. In this chapter, the estimates and measures of trust fund financial adequacy for the short range (2008-17) are presented first, followed by esti­mates and measures of actuarial status for the long range (2008‑82) and for the infinite future. As an additional illustration of uncertainty, estimated probability distributions of certain measures are presented in Appendix E.
A. SHORT-RANGE ESTIMATES
Financial adequacy, or solvency, of the trust funds reflects the ability to pay scheduled benefits in full on a timely basis and is generally assessed using the “trust fund ratio,” which is defined as the assets at the beginning of a year expressed as a percentage of the projected cost for the year. Thus, the trust fund ratio represents the proportion of a year’s cost which can be paid with the funds available at the beginning of the year. A trust fund ratio of 100 per­cent of annual program cost is generally assumed to provide a reasonable “contingency reserve.” During periods when trust fund income exceeds dis­bursements, the excess is held in the trust funds. To the extent that trust fund assets exceed 100 percent of annual cost, the excess is dedicated to advance fund a portion of the Social Security program’s future financial obligations. During periods when trust fund disbursements exceed income, as might hap­pen during an economic recession, trust fund assets are used to meet the shortfall. In the event of recurring shortfalls for an extended period, the trust funds can allow time for the development, enactment, and implementation of legislation to restore financial stability to the program.
The short-range test of financial adequacy is applicable to the OASI and DI Trust Funds individually and on a combined basis. The requirements of this test are as follows: If the estimated trust fund ratio is at least 100 percent at the beginning of the projection period, then it must be projected to remain at or above 100 percent throughout the 10-year projection period. Alterna­tively, if the ratio is initially less than 100 percent, then it must be projected to reach a level of at least 100 percent within 5 years and to remain at or above 100 percent throughout the remainder of the 10-year period. In addi­tion, the fund’s estimated assets at the beginning of each month of the 10-year period must be sufficient to cover that month’s disbursements. This test is applied on the basis of the intermediate estimates. Failure to meet this test by either trust fund is an indication that solvency of the program over the next 10 years is in question and that legislative action is needed to improve the short-range financial adequacy of the program.
1. Operations of the OASI Trust Fund
This subsection presents estimates of the operations and financial status of the OASI Trust Fund for the period 2008-17, based on the assumptions described in chapter V. No changes are assumed to occur in the present statu­tory provisions and regulations under which the OASDI program operates.1
These estimates are shown in table IV.A1 and indicate that the assets of the OASI Trust Fund would continue to increase rapidly throughout the next 10 years under all three sets of assumptions. Also, based on the intermediate assumptions, the assets of the OASI Trust Fund would continue to exceed 100 percent of annual expenditures by a large amount through the end of 2017. Consequently, the OASI Trust Fund satisfies the test of short-range financial adequacy by a wide margin. The estimates in table IV.A1 also indi­cate that the short-range test would be satisfied even under the high cost assumptions (see figure IV.A1 for graphical illustration of these results).
The increases in estimated income shown in table IV.A1 under each set of assumptions reflect increases in estimated OASDI taxable earnings and growth in interest earnings on the invested assets of the trust fund. For each alternative, employment and earnings are assumed to increase in every year through 2017, except for two periods of economic recession in alternative III. The number of persons with taxable earnings would increase on the basis of alternatives I, II, and III from 163 million during calendar year 2007 to about 178 million, 175 million, and 172 million, respectively, in 2017. The total annual amount of taxable earnings is projected to increase from $5,300 billion in 2007 to $8,329 billion, $8,422 billion, and $8,758 billion, in 2017, on the basis of alternatives I, II, and III, respectively.2 These increases in taxable earnings are due primarily to (1) projected increases in employment levels as the working age population increases, (2) increases in average earnings in covered employment (reflecting both real growth and price inflation), and (3) increases in the contribution and benefit base in 2008-17 under the automatic-adjustment provisions.
Growth in interest earnings represents a significant component of the overall increase in trust fund income during this period. Although interest rates pay­able on trust fund investments are not assumed to change substantially from current levels, the continuing rapid increase in OASI assets will result in a corresponding increase in interest income. By 2017, interest income to the OASI Trust Fund is projected to be about 20 percent of total trust fund income on the basis of the intermediate assumptions, as compared to 14 percent in 2007.
 
Figure IV.A1.—Short-Range OASI and DI Trust Fund Ratios[Assets as a percentage of annual cost]
 
Net
contri-
butions
Taxa-
tion of
benefits
Net
interest
Benefit
pay-
ments
Admin-
istra-
tive
costs
RRB
inter-
change
Net
increase
during
year
Amount
at end
of year
Trust
fund
ratio 3

1
A detailed description of the components of income and cost, along with complete historical values, is pre­sented in Appendix A.

2
“Total Income” column includes transfers made between the OASI Trust Fund and the General Fund of the Treasury that are not included in the separate components of income shown. These transfers consist of pay­ments for (1) the cost of noncontributory wage credits for military service before 1957, and (2) the cost of benefits to certain uninsured persons who attained age 72 before 1968. In December 2005, $350 million was transferred from the OASI Trust Fund to the General Fund of the Treasury for the cost of pre-1957 military service wage credits. After 2007 such transfers are estimated to be less than $500,000 in each year.

3
The “Trust fund ratio” column represents assets at the beginning of a year (which are identical to assets at the end of the prior year shown in the “Amount at end of year” column) as a percentage of cost for the year.

Note: Totals do not necessarily equal the sums of rounded components.
Rising expenditures during 2008-17 reflect automatic benefit increases as well as the upward trend in the number of beneficiaries and in the average monthly earnings underlying benefits payable by the program. The growth in the number of beneficiaries in the past and the expected growth in the future result both from the increase in the aged population and from the increase in the proportion of the population which is eligible for benefits.
The estimates under all three sets of assumptions shown in table IV.A1 indi­cate that income to the OASI Trust Fund would substantially exceed expen­ditures in every year of the short-range projection period, and assets are therefore estimated to increase substantially.
The portion of the OASI Trust Fund that is not needed to meet day-to-day expenditures is used to purchase financial securities, generally special pub­lic-debt obligations of the U.S. Government. The cash used to make these purchases flows to the General Fund of the Treasury and is used to meet var­ious Federal outlays or to reduce the amount of publicly-held Federal debt. Interest on these securities is credited to the trust fund and, when the securi­ties mature, they are reinvested in new securities if not immediately needed to pay program costs. When securities are redeemed prior to maturity in order to pay program costs, general fund revenues flow to the trust fund. Thus, the investment operations of the trust fund result in various credits and cash flows between the trust fund and the General Fund of the Treasury.
2. Operations of the DI Trust Fund
The estimated operations and financial status of the DI Trust Fund during calendar years 2008-17 under the three sets of assumptions are shown in table IV.A2, together with values for actual experience in 2003-07. Income is generally projected to increase steadily under each alternative, reflecting most of the same factors described previously in connection with the OASI Trust Fund. The estimates indicate that the assets of the DI Trust Fund would also continue to increase throughout the next 10 years under the low cost assumptions, but would peak in 2011 and then begin to decline under the intermediate assumptions. Under the high cost assumptions, DI assets would decline steadily beginning in 2008 until exhaustion in 2017.
Cost is estimated to increase in part due to increases in average benefit levels resulting from (1) automatic benefit increases and (2) projected increases in the amounts of average monthly earnings on which benefits are based. In addition, under all three sets of assumptions, the number of DI beneficiaries in current-payment status is projected to continue increasing throughout the short-range projection period. Over the period 2007-17, the projected annual average growth rate in the number of DI worker beneficiaries is roughly 1.2, 2.5, and 3.6 percent under alternatives I, II, and III, respectively. Growth is largely attributable to the gradual progression of the baby-boom generation through ages 50 to normal retirement age, at which higher rates of disability incidence are experienced.
Annual increases in incidence rates over the period 2001-03 represented a notable departure from the experience of the preceding decade, which gener­ally showed modest annual declines in the age-sex-adjusted disability inci­dence rate.3 During 2004 and 2005 however, this growth in the incidence rate subsided, and the incidence rate even declined in 2006 and 2007. Never­theless, incidence rates are still at a level somewhat higher than experienced during the late 1990s. The increases in 2001-03 were likely due in large part to the slowdown in economic growth experienced during that period. How­ever, a special administrative activity undertaken by SSA beginning in 2001 has also contributed slightly to the upsurge in disabled worker awards. This special workload was the result of discovering a substantial number of cur­rent or former recipients of Supplemental Security Income (SSI) benefits whose disability insured status under the DI program was not previously rec­ognized. As this special disability workload continues to be processed over the next several years, the resulting disability awards will contribute to tem­porarily higher incidence rates than would have been expected as part of longer term underlying trends.
Estimates of the total size of this special workload, and the schedule for pro­cessing these cases, remain roughly the same as assumed for the 2007 report. After the last of these special workload cases is processed in about 2010, the incidence of disability is projected in this report to drop back somewhat from then current levels, and to remain roughly level on an age-sex-adjusted basis over the remainder of the short-range period under the intermediate assump­tions. Incidence rates gradually rise under alternative III, and decline under alternative I, after 2010 to the end of the short-range period.
 
Table IV.A2.—Operations of the DI Trust Fund, Calendar Years 2003-171 [Amounts in billions]
Net
contri-
butions
Taxa-
tion of
benefits
Net
interest
Benefit
pay-
ments
Admin-
istra-
tive
costs
RRB
inter-
change
Net
increase
during
year
Amount
at end
of year
Trust
fund
ratio 3
4/

1
A detailed description of the components of income and cost, along with complete historical values, is pre­sented in Appendix A.

2
“Total Income” column includes transfers made between the DI Trust Fund and the General Fund of the Treasury that are not included in the separate components of income shown. These transfers consist of pay­ments for the cost of noncontributory wage credits for military service before 1957. In particular, a transfer was made in December 2007 in the amount of $7.7 million from the General Fund of the Treasury to the DI Trust Fund. After 2007 such transfers are estimated to be less than $500,000 in each year.

3
The “Trust fund ratio” column represents assets at the beginning of a year (which are identical to assets at the end of the prior year shown in the “Amount at end of year” column) as a percentage of cost for the year.

4
Under the high cost assumptions, the DI Trust Fund is projected to be exhausted in 2017. Therefore, certain trust fund operation values for that year are not meaningful under present law and are not shown in this table.

Note: Totals do not necessarily equal the sums of rounded components.
The proportion of DI beneficiaries whose benefits terminate in a given year has also fluctuated in the past. Over the last 20 years, the rates of benefit ter­mination due to death or conversion to retirement benefits (at attainment of normal retirement age) have declined very gradually. This trend is attribut­able, in part, to the lower average age of new beneficiaries. Declines in mor­tality for the general population have also led to improved mortality experience among the DI disabled-worker beneficiaries. In addition, conver­sions to old-age benefits are at a temporarily reduced level for years 2003 through 2008 due to the gradual increase in the normal retirement age. The termination rate due to recovery has been much more volatile. Currently, the proportion of disabled beneficiaries whose benefits cease because of their recovery from disability is very low in comparison to levels experienced throughout the 1970s and early 1980s. Projected rates of recovery termina­tions in this year’s report are low initially due to resource constraints which temporarily limit the number of continuing disability reviews conducted by SSA. Following this temporary resource constraint, recovery termination rates are projected to return to levels consistent with last year’s report. The overall proportion of disabled workers leaving the DI rolls (reflecting all causes) is projected in 2008 to remain near levels experienced since 2003, before returning to higher levels in 2009 when the gradual increase in the normal retirement age temporarily ceases.
At the beginning of calendar year 2007, the assets of the DI Trust Fund rep­resented 206 percent of annual expenditures. During 2007, DI expenditures continued to exceed non-interest income. While total DI income exceeded DI expenditures by $11.1 billion, the trust fund ratio for the beginning of 2008 still decreased, to about 199 percent. Under the intermediate set of assump­tions, total income is estimated to exceed expenditures through 2011. The projected expenditures in excess of income beginning in 2012 result in a decline in the projected trust fund ratio to 107 percent by the beginning of 2017.
Under the low cost assumptions, the trust fund ratio would increase to 225 percent at the beginning of 2017. Under the high cost assumptions, the assets of the DI Trust Fund would decline steadily, dipping below the level of 1 year’s expenditures near the beginning of 2013, and becoming com­pletely depleted in 2017.
Assets of the DI Trust Fund were greater than 1 year’s expenditures at the beginning of 2008 and would remain above that level through the beginning of 2017. By the beginning of 2018, however, the trust fund ratio is projected to decline to 95 percent, indicating that assets would fall below the 100-per­cent level sometime during 2017. Accordingly, the DI Trust Fund does not satisfy the Trustees’ short-range test of financial adequacy under both the intermediate and high cost assumptions. However, under the low cost assumptions the DI Trust Fund does meet the short-range test of financial adequacy, because assets remain above 1 year’s expenditures through the end of the short-range period, as described above (see also figure IV.A1).
 
3. Operations of the Combined OASI and DI Trust Funds
The estimated operations and status of the OASI and DI Trust Funds, com­bined, during calendar years 2008-17 on the basis of the three alternatives, are shown in table IV.A3, together with figures on actual experience in 2003‑07. Because income and cost for the OASI Trust Fund represent over 80 percent of the corresponding amounts for the combined OASI and DI Trust Funds, the operations of the OASI Trust Fund tend to dominate the combined operations of the two funds. Consequently, based on the strength of the OASI Trust Fund over the next 10 years, the combined OASI and DI Trust Funds meet the requirements of the short-range test of financial ade­quacy under all three alternative sets of assumptions.
While combining the operations of the OASI and DI Trust Funds permits an assessment of the short-range test for the two programs on a combined basis, in practice assets from one trust fund cannot be shared with another trust fund without legislative changes to the Social Security Act. For example, under the high cost scenario, table IV.A2 shows that the DI Trust Fund becomes exhausted in 2017. The value of the combined OASI and DI Trust Funds in that year shown in table IV.A3 shows that OASI assets could be made available to pay DI benefits through 2017, but only with legislation to permit this action.
 
Table IV.A3.—Operations of the Combined OASI and DI Trust Funds,
Calendar Years 2003-17 1 [Amounts in billions]
Net
contri-
butions
Taxa-
tion of
benefits
Net
interest
Benefit
pay-
ments
Admin-
istra-
tive
costs
RRB
inter-
change
Net
increase
during
year
Amount
at end
of year
Trust
fund
ratio 3

1
A detailed description of the components of income and cost, along with complete historical values, is pre­sented in Appendix A.

2
“Total Income” column includes transfers made between the OASI and DI Trust Funds and the General Fund of the Treasury that are not included in the separate components of income shown. These transfers con­sist of payments for (1) the cost of noncontributory wage credits for military service before 1957, and (2) the cost of benefits to certain uninsured persons who attained age 72 before 1968.

3
The “Trust fund ratio” column represents assets at the beginning of a year (which are identical to assets at the end of the prior year shown in the “Amount at end of year” column) as a percentage of cost for the year.

Note: Totals do not necessarily equal the sums of rounded components.
4. Factors Underlying Changes in 10-Year Trust Fund Ratio Estimates From the 2007 Report
The factors underlying the changes in the intermediate estimates for the OASI, DI and the combined funds from last year’s annual report to this report are analyzed in table IV.A4. In the 2007 Annual Report, the trust fund ratio for OASI was estimated to reach 462 percent at the beginning of 2016—the tenth projection year from that report. If there had been no changes to the projections, the estimated ratio at the beginning of 2017 would be 4 percentage points lower than at the beginning of 2016, or 458 percent. There were changes, however, to reflect the latest actual data, as well as adjustments to the assumptions for future years. The resulting ratio shown in this report for the tenth projection year (2017) is 438 percent. The net effect of changes in demographic assumptions over the short-range period resulted in a reduction in the tenth-year trust fund ratio of 3 percent­age points. The cumulative net effects of changes in economic data and assumptions resulted in a reduction in the trust fund ratio of 15 percentage points by the beginning of 2017. There were several relatively minor changes in the short-range projection methodology since the 2007 report. The changes included improvements in our methods for estimating the numbers of retired workers and their retirement rates. In addition, the revision in the methods used for projecting the other-immigrant (other than legal permanent resident) population described in section IV.B.7 had an impact on estimated revenue in the short-range period. The combined effect of these methodolog­ical improvements was to increase the ending trust fund ratio by about 2 per­centage points. Finally, a decrease in the 2017 trust fund ratio of 3 percentage points resulted from the combined effects of incorporating recent programmatic data including the correction of the trust fund allocation error described in section III.A. As discussed in section III.B, no legislative changes have been enacted since the 2007 report that directly affect the financing of the OASDI program.
Corresponding estimates of the factors underlying the changes in the finan­cial projections for the DI Trust Fund, and for the OASI and DI Trust Funds combined, are also shown in table IV.A4. The largest effects on the DI trust fund ratio at the beginning of 2017 were due to the change in the valuation period and revised economic assumptions, which make up essentially all of the net 23 percentage point reduction. Revised demographic assumptions, updates for a variety of programmatic assumptions (including the correction of the trust fund allocation error), and improvements to DI projection meth­odology contributed minor offsetting changes.
 
Table IV.A4.—Reasons for Change in Trust Fund Ratios at the Beginning
of the Tenth Year of Projection[In percent]
OASI
Trust Fund
DI
Trust Fund
OASI and DI
Trust Funds,
combined

1
Change in trust fund ratio of less than 0.5 percentage point.

Note: Totals do not necessarily equal the sums of rounded components.

1
The estimates shown in this subsection reflect 12 months of benefit payments in each year of the short-range projection period. In practice, the actual payment dates have at times been shifted over calendar year boundaries as a result of the statutory requirement that benefit checks be delivered early when the normal check delivery date is a Saturday, Sunday, or legal public holiday. The annual benefit figures are shown as if those benefit checks were delivered on the usual date.

2
Note that the pattern, by alternative, of these nominal amounts of total taxable earnings is not what might be expected, but the reverse, because of the varying inflation assumptions embedded in the respective esti­mates.

3
Historical and projected patterns of disability incidence rates are described in greater detail in section