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Smithsonian Institution capital-construction payment oversight

Smithsonian Approved Hirshhorn Bills It Never Checked

Summary

A Smithsonian Inspector General audit of the Hirshhorn Museum Sculpture Garden's $72.9 million revitalization found the project team approved contractor invoices without checking whether the percentages of work billed as complete matched the contractor's own construction schedule. Of 639 billed work items OIG tested, 262 didn't reconcile -- swings that ran as high as $967,406 potentially over-invoiced in a single month, against $20.1 million already paid out.

By Marcus Aurelius · July 20, 2026

A Smithsonian Institution Office of the Inspector General audit published March 31, 2026 found the team overseeing the Hirshhorn Museum Sculpture Garden's $72.9 million revitalization approved contractor invoices without reconciling them to the contractor's own construction schedule. Testing all 639 work items billed across seven monthly payment applications, auditors found 262 didn't match -- billing swings that ran as high as $967,406 potentially over-invoiced in a single month, against $20.1 million the Smithsonian had already paid out.

A contract tested at 28 cents on the dollar

In September 2023, the Smithsonian awarded a firm-fixed-price contract to revitalize the Hirshhorn's Sculpture Garden -- fixing waterproofing failures and concrete decay from the garden's original 1974 construction, and adding stormwater management the sunken plaza has never had. Each month, the contractor submits an application for payment built around a Schedule of Values (SOV): an itemized list of work with a percentage of completion assigned to each line. Separately, the contractor keeps a Progress Schedule tracking the same work against its planned timeline. The contract requires the two documents to line up -- the SOV's percentages are supposed to be supported by the Progress Schedule, not just asserted alongside it.

By September 18, 2024, the Smithsonian's Office of the Inspector General reports it had approved 10 of these monthly applications, worth $20,106,616 against the project's $72,851,754 total cost -- about 28 cents of every contract dollar. 's audit tested all of it: every work item billed in the seven applications for which a Progress Schedule existed.

Approved so far
$20.1M
of $72.9M total project cost, across 10 applications for payment approved through Sept. 2024
Billed items that didn't reconcile
262 of 639
41% of tested work items didn't match the contractor's own Progress Schedule
Largest single-month swing
$967,406
potentially over-invoiced in Application No. 7 alone
What OIG found when it checked the Hirshhorn contractor's bills
639 billed work items tested against the contractor's own Progress Schedule
Matched the Progress Schedule
377
Billed percentage unsupported by schedule
148
Billed item missing from schedule entirely
114
Source: Smithsonian Institution OIG, Hirshhorn Museum Sculpture Garden Revitalization Project's Applications for Payment Process (OIG-A-26-07), March 31, 2026 (Audit Results, p. 6)
View data as table
OIG compared percentages of completion for 639 work items billed across Applications for Payment No. 4-10 (Nos. 1-3 were excluded; no Progress Schedule was submitted for that period) to the Contractor's Progress Schedule. 377 items matched. 262 didn't: 148 had a billed percentage the schedule didn't support -- about half billed higher than the schedule showed, which OIG said risks the Smithsonian paying for uncompleted work -- and 114 were billed with no matching entry in the schedule at all.
Matched the Progress Schedule377No discrepancy found between the billed percentage and the contractor's own schedule
Billed percentage unsupported by schedule148Progress Schedule didn't back up the percentage billed; about half were billed higher than the schedule showed
Billed item missing from schedule entirely114Work item appeared on the payment application with no matching entry in the Progress Schedule

The reconciliation the contract required never happened

Of 639 work items tested, 262 -- 41 percent -- showed a discrepancy between what the SOV billed and what the Progress Schedule supported. In 148 cases, the schedule simply didn't back up the percentage billed; in about half of those, the Smithsonian had approved payment for more work than the schedule showed as done, which said risks paying for work that wasn't actually complete. In the other 114 cases, the SOV billed for a work item that didn't appear on the Progress Schedule at all. The Contracting Officer's Technical Representative (COTR) who approves each application told the two documents' work items "did not always align," making a real reconciliation "difficult, if not impossible" -- an explanation didn't accept, since the contract requires the alignment regardless of how the paperwork was organized.

How far each month's bill strayed from the contractor's own schedule
Amount the Contractor potentially over- or under-invoiced, by application for payment
Application No. 4 -- under-invoiced
365,421
Application No. 5 -- under-invoiced
614,761
Application No. 6 -- over-invoiced
318,572
Application No. 7 -- over-invoiced
967,406
Application No. 8 -- under-invoiced
507,765
Application No. 9 -- over-invoiced
510,205
Application No. 10 -- over-invoiced
396,755
Source: Smithsonian Institution OIG, Hirshhorn Museum Sculpture Garden Revitalization Project's Applications for Payment Process (OIG-A-26-07), March 31, 2026 (Table 1, p. 7; Appendix C)
View data as table
Bar length is the size of the mismatch between what the Contractor billed and what the Progress Schedule supported for that month's application; each bar's label states whether the SOV came in above (over-invoiced) or below (under-invoiced) the schedule. OIG found these amounts cannot be netted into one total because the Contractor's billing is cumulative -- each application's Schedule of Values reflects running totals, not a fresh monthly balance.
Application No. 4 -- under-invoiced365,421$365,421 less than what the Progress Schedule supported
Application No. 5 -- under-invoiced614,761$614,761 less than what the Progress Schedule supported
Application No. 6 -- over-invoiced318,572$318,572 more than what the Progress Schedule supported
Application No. 7 -- over-invoiced967,406$967,406 more than what the Progress Schedule supported -- the largest swing OIG found
Application No. 8 -- under-invoiced507,765$507,765 less than what the Progress Schedule supported
Application No. 9 -- over-invoiced510,205$510,205 more than what the Progress Schedule supported
Application No. 10 -- over-invoiced396,755$396,755 more than what the Progress Schedule supported

One month's bill was off by nearly a million dollars

Application No. 7 shows the size of the gap: 's comparison put the Smithsonian $967,406 over what the contractor's own Progress Schedule supported for that month, the largest single swing in the sample. Other months ran the other way -- Application No. 5 came in $614,761 under what the schedule would have supported. stressed these per-application figures can't be added into one running total, because the contractor's billing is cumulative rather than a fresh monthly balance. What they show instead is that no month in the sample reconciled cleanly, in either direction.

The stakes turn on what happens if the project doesn't finish as planned. If the contractor completes the work as billed, 's finding is a paperwork problem -- a timing mismatch between two schedules that should have matched from the start. But if a dispute forced the Smithsonian to terminate the contract early, the Smithsonian would have no reconciled record showing which of the $20.1 million already paid was actually earned -- meaning it could be left having paid for garden work that was never finished.

  • 262 of 639 billed work items -- 41 percent -- didn't reconcile to the contractor's own Progress Schedule, across the seven Hirshhorn Sculpture Garden payment applications could test.
  • In 148 of those cases the schedule didn't support the percentage billed, and in about half of those the Smithsonian had approved payment for more work than the schedule showed complete -- 's stated risk: paying for work that wasn't done.
  • Monthly swings ran as high as $967,406 potentially over-invoiced (Application No. 7) and $614,761 potentially under-invoiced (Application No. 5), on a project where $20.1 million of $72.9 million total cost had been billed as of September 2024.
  • The Contracting Officer's Technical Representative approved every application without comparing the two documents, telling the mismatched paperwork made reconciliation "difficult, if not impossible" -- despite a contract clause requiring exactly that reconciliation.
  • Management concurred with 's single recommendation but doesn't have to fix it until December 31, 2026 -- around the same time the whole Sculpture Garden revitalization is due to finish.

's review covered all 10 applications for payment approved as of September 18, 2024 and all 639 corresponding work items -- a full test of the available record, not a sample. Applications No. 1 through 3 (October 2023-February 2024) were excluded because the contractor hadn't yet submitted a Progress Schedule for that period. A discrepancy is not proof of an overpayment: 's findings describe amounts the contractor "potentially" over- or under-invoiced relative to what the Progress Schedule alone would support, not confirmed losses, and the audit did not allege fraud. Smithsonian management concurred with 's recommendation to document reconciliation of future applications against future Progress Schedules; as of the report date, considered it resolved but open, with a target completion date of December 31, 2026. This piece describes the finding by role (the COTR, the Contractor) rather than by name, consistent with the audit itself.

Sources(2) ▾
  • Smithsonian Institution Office of the Inspector General, Hirshhorn Museum Sculpture Garden Revitalization Project's Applications for Payment Process (OIG-A-26-07) (2026-03-31)A performance audit by Sikich CPA LLC, engaged by the Smithsonian Institution's Office of the Inspector General, transmitted March 31, 2026. The audit tested whether the Smithsonian approved the Hirshhorn Sculpture Garden revitalization contractor's monthly applications for payment -- all 10 approved as of September 18, 2024, totaling $20,106,616 -- in compliance with the contract's requirement that billed percentages of completion be supported by the contractor's own Progress Schedule. Hosted on oversight.gov, the Council of the Inspectors General on Integrity and Efficiency's official federal- portal; the Smithsonian 's own report page (oig.si.edu) links directly to this file. Note: the report's two-page "In Brief" summary states the total project cost as $72,815,754, while the full report body (Methodology, p. 2) states $72,851,754 -- an apparent digit transposition between the two; this piece uses the body figure as the more detailed methodological citation. oversight.gov · original document
  • Smithsonian Institution Office of the Inspector General, OIG Hotline (2026-07-20)The Smithsonian 's public hotline page, re-fetched this iteration to source the call-to-action contact details in this piece: phone, email, mailing address, and online complaint form for reporting fraud, waste, and abuse in Smithsonian programs and operations -- the same office that produced the audit this article covers. oig.si.edu · original document
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