This is a concept elicitation study to identify important aspects of pain assessment, treatment, and response to treatment in children under than 3 years of age from a caregiver's perspective.

The purpose of this study is to identify important endpoints and outcomes for use in pediatric trials for acute pain therapeutics in infants and young children from a caregiver's perception. Study team members will conduct phone-based qualitative interviews, using a semi-structured interview guide, with 42 primary caregivers of pediatric patients under 3 years of age who are experiencing or have experienced acute pain. Once participants give verbal consent, they will fill out a demographics form. Interviews will last about one hour and will address the participant's experience recognizing and managing their child's acute pain. The investigators will use these concept elicitation interviews to identify important aspects of acute pain assessment, treatment, and response to treatment in children who are under 3 years old. Interviews will be audio recorded and transcribed with participant permission. Transcripts or interviewer notes will be reviewed by two analysts and will be double coded until inter-rater reliability is reached by agreement of at least 80%. The study team will conduct a thematic analysis of the coded transcripts. This is a minimal risk study. All information will be kept confidential and information will be stored on a secure network which is only accessible to the study team.

Inclusion Criteria:

1. Cares for a child who is both:

   • Between 0 and <3 years of age
   • Experiencing or has experienced acute pain in one of the following categories:
   • Malignant or non-malignant visceral or hematologic disease
   • Surgery (or other procedure)
   • Trauma or injury
   • Congenital conditions

2. Is over the age of 18 years old.

3. Can speak and understand English.

4. Is capable of and willing to provide informed consent for interview participation and to collect medical data from the child's medical record.

Exclusion Criteria:

1. Lack of access to a telephone or computer for interview
2. Has a child with acute pain that is extremely premature (less than 32 weeks gestation at the time of enrollment) and no other eligible child.

The study population will be caregivers of children 0 to <3 years old who have experienced acute pain. Eligible caregivers will be identified by Pediatric Trials Network sites across the United States. Eligible participants will be identified through recruitment for a pre-existing Pediatric Trials Network study called Pharmacokinetics and Safety of Anesthetics and Analgesics in Children and Adolescents.

Individual participant data will not be shared outside of the study team.