Present capabilities for precision and accuracy are compared with the needs at the working level. A measurements structure is sketched by which reference standards accuracies are propagated. Uncertainties are prescribed for a number of prevalent measurement methods including precision U-tube manometer, McLeod gauge, volumetric pressure division, and dynamic expansion. The development at the National Bureau of Standards of direct absolute measurements standards of high precision and their use in dynamic environments stabilized to better than one part in 103 and ranging from the medium to the ultrahigh vacuum are described. These methods include precision liquid columns for the upper pressure range, interferometer manometer and modified McLeod gauges for the high vacuum range, and a torsion microbalance or Vane gauge for the ultrahigh vacuum range.