vars_ph_p_sds__swtd: Compute "Sleep Disturbance Scale [Parent] (Sleep-wake transition
disorders): Sum [Validation: No more than 0 missing or declined]"
Description
Computes the summary score ph_p_sds__swtd_sum
Sleep Disturbance Scale [Parent] (Sleep-wake transition disorders): Sum
[Validation: No more than 0 missing or declined]