There is an increasing interest in using short rod and short bar fracture toughness specimens to measure the plane-strain critical stress-intensity factor of metallic materials. In this paper, short rod and short bar specimen design considerations are discussed, and various specimen geometries with essentially equivalent test behavior and calibration are presented. A recent experimental study was conducted on three steels and two aluminum alloys to determine the sensitivity of the test result to variations in the chevron slot thickness and the sharpness of the slot bottoms. The results give strong indications that plane-strain constraint along the crack front is enhanced by thinness of the chevron slots and sharpness of the slot bottoms. The desirable aspects of loading configurations for short rod testing are discussed, and a successful loading mechanism is described.