This bill aims to expand eligibility for the working families' tax credit in Washington State to include all individuals aged 18 and older. It amends existing law to redefine "eligible low-income person" to include those who would qualify for the credit under the Internal Revenue Code but do not meet the age requirement, as long as they are at least 18 by the end of the prior federal tax year. Additionally, the bill clarifies that individuals who file their federal tax returns using a valid individual taxpayer identification number (ITIN) can also qualify for the credit, provided their spouse and qualifying children have valid identification numbers.

The bill also establishes a performance statement for the tax preference associated with the working families' tax credit, emphasizing the legislature's intent to provide financial relief to low- and middle-income workers. It mandates a review of the program every ten years, starting in 2028, to assess its effectiveness in providing meaningful financial relief. If the review finds the credit inadequate, the law will expire two years after the report's adoption. The act is set to take effect on January 1, 2024, and includes provisions for the department of revenue to administer the credit and protect the privacy of recipients.