Table:
| (in million) | 2019 | 2018 |
| --- | --- | --- |
| Trade accounts receivable | $526.6 | $469.2 |
| Less: Allowance for doubtful accounts | (2.2) | (2.3) |
| Product returns reserve | (0.3) | (0.2) |
| Partner programs and other obligations | (49.8) | (28.5) |
| Accounts receivable, net (1) | $474.3 | $438.2 |
Paragraphs:
Accounts Receivable, Net
Accounts receivable, net, consisted of the following as of January 31:
(1) Autodesk adopted ASU No. 2014-09, “Revenue from Contracts with Customers" regarding Accounting Standards Codification (ASC Topic 606) during the first quarter of fiscal 2019. As such, current year balances are shown under ASC Topic 606 and prior year balances are shown under ASC Topic 605. See Note 1, "Business and Summary of Significant Accounting Policies-Accounting Standards Adopted", of our consolidated financial statements for additional information.
Allowances for uncollectible trade receivables are based upon historical loss patterns, the number of days that billings are past due, and an evaluation of the potential risk of loss associated with problem accounts.
As part of the indirect channel model, Autodesk has a partner incentive program that uses quarterly attainment of monetary rewards to motivate distributors and resellers to achieve mutually agreed upon business goals in a specified time period. A portion of these incentives reduce maintenance and other revenue in the current period. The remainder, which relates to incentives on our Subscription Program, is recorded as a reduction to deferred revenue in the period the subscription transaction is billed and subsequently recognized as a reduction to subscription revenue over the contract period. These incentive balances do not require significant assumptions or judgments. Depending on how the payments are made, the reserves associated with the partner incentive program are treated on the balance sheet as either contra accounts receivable or accounts payable
Question:
What are allowances for uncollectible trade receivables based on?
Answer: historical loss patterns, the number of days that billings are past due, and an evaluation of the potential risk of loss associated with problem accounts.