What is the effect on the income statement when the allowance for uncollectible accounts is not established?

Without the balance sheet account, Allowance for Uncollectible Accounts, all of the accounts receivable are assumed to be collectible and there is no bad debt expense reported on the income statement until an account receivable is written off. This approach is known as the direct write-off method. (When an account is written off, the entry will be a debit to Bad Debt Expense and a credit to Accounts Receivable.)

The income will be Overstated.

there will not be  bad debt expense  in the income statement

It will increase the profit since it is uncollectible accounts.