Purpose: To establish intervention fidelity of the premature infant oral motor intervention (PIOMI)

Design and sample: A rating tool was developed and tested for interrater reliability before being used to test the fidelity of intervention behaviors. A purposeful convenience sample of three users was recruited to perform the intervention under direct observation.

Main outcome variables: Three types of reliabilities were calculated: (1) interrater reliability to test the rating tool, followed by (2) interuser reliability, and (3) test–retest reliabilities to test the intervention behaviors of several registered nurses (RNs) over repeated performances of the intervention.

Results: The rating tool demonstrated a high interrater reliability (97.57 percent), indicating its accuracy for systematically rating the specific intervention behaviors. Subsequently, the rating tool was used to determine interuser and test–retest performances of the PIOMI and resulted in high reliabilities (97.59 percent and 97.58 percent, respectively). This demonstrates that the intervention can be reliably delivered as prescribed, supporting intervention fidelity.