Republican lawmakers, continuing their focus on the Dodd-Frank financial overhaul, want the regulatory agencies writing the rules to justify costs associated with the new regulations.

On Tuesday, Texas Republican Rep. Michael Conaway plans to introduce legislation that would require the Commodity Futures Trading Commission to assess the costs and benefits of rules it proposes, including the impact on market liquidity, according to congressional aides.

Meanwhile, a group of GOP senators on Monday requested inspector general reviews of “economic analyses” being performed by all regulatory agencies writing Dodd-Frank rules. A letter, signed by 10 Republican members of the Senate Banking Committee, says the Dodd-Frank rules “will have a long-term effect on economic growth” and that “Democrats paid little attention to the potential costs of Dodd-Frank before the fact.”

The moves come on the heels of an IG review of four CFTC rules that found the agency relied more heavily on input from its general counsel than its Office of Chief Economist. That IG report was requested by Mr. Conaway and other GOP lawmakers…