AUSTIN — Advocacy groups on the left and the right rarely get the attention of major political committees and business associations, but these issue-based organizations are spending millions of dollars to influence public policy at the state Capitol.

Most don't have committees that finance candidates. Many don't have lobbyists working the Capitol hallways.

These groups try to sway the minds of voters and policymakers through statistical reports, analyses and databases. Most of the groups' funding sources are secret, except for public foundations that may donate money.