## Facts

- Curtis McDonald and Yvonne Trihub, never married, had one child (born 1992) and separated when the child was an infant.
- McDonald voluntarily paid varying child support for years without a court order.
- In 1999, Trihub and the child returned to Alaska and lived with McDonald until May 2000.
- In 2003, Trihub sought child support through an administrative agency; an amended administrative order set ongoing support and found arrears for a limited period.
- In a separate superior court action, Trihub sought to establish support for earlier periods, including back to May 2000.
- The superior court found McDonald’s financial evidence confusing and not credible, could not reconstruct his actual income, and imputed income using local labor-market wage data for his work history.
- The superior court calculated support (including retroactive support), rejected McDonald’s claimed shared-physical-custody classification, declined to reduce support based on alleged disability, and awarded attorney’s fees under the general civil fee rule.
- McDonald appealed these determinations.

## Issues

1. Whether McDonald’s conduct waived collateral estoppel such that the superior court could determine support obligations notwithstanding the administrative order.
2. Whether the superior court’s retroactive support award was an impermissible retroactive modification of child support.
3. Whether the superior court clearly erred by finding McDonald did not have shared physical custody for support-calculation purposes.
4. Whether the superior court erred by imputing income based on labor-market data rather than using McDonald’s asserted actual income.
5. Whether the superior court erred by refusing to reduce child support due to McDonald’s claimed disability.
6. Whether attorney’s fees were properly awarded under Alaska Civil Rule 82 rather than a domestic-relations “divorce exception.”

## Decision

- The Alaska Supreme Court affirmed the superior court in all respects.
- Collateral estoppel was not available because McDonald affirmatively waived it by litigating annual support obligations in superior court rather than treating the administrative order as binding.
- The retroactive award was not an impermissible retroactive modification because no valid support order governed the periods established by the superior court.
- The finding that McDonald did not have shared physical custody was supported by the record.
- Income imputation was upheld because McDonald’s income evidence was unreliable and the court reasonably used wage data tied to his work history.
- The court properly declined a disability-based reduction because the record supported continued earning capacity at the imputed level.
- Attorney’s fees under Civil Rule 82 were proper, and the asserted “divorce exception” did not apply on these facts.

## Legal Principles

- Collateral estoppel can be waived by a party’s litigation conduct, including inviting a court to decide issues allegedly resolved elsewhere.
- A support award covering a period not governed by a valid existing support order is an initial establishment of support, not a prohibited retroactive modification.
- Physical-custody classifications for child support depend on the actual pattern of care; factual findings are reviewed for clear error.
- When a parent’s actual income cannot be reliably determined due to inadequate or non-credible evidence, a court may impute income using work history and local wage data.
- A claimed disability does not automatically reduce child support; the obligor must show a material impairment of earning capacity.
- In non-divorce child-support litigation, Alaska Civil Rule 82 generally governs attorney’s fees absent a specifically applicable exception.

## Conclusion

The Alaska Supreme Court affirmed a superior court child-support order that differed from an earlier administrative determination because the obligor waived preclusion, the court was establishing (not retroactively modifying) support for periods without a valid governing order, and the court permissibly imputed income, rejected shared-custody and disability reductions on the record, and awarded fees under Civil Rule 82.


McDonald v. Trihub, 173 P.3d 416 (Alaska 2007)