There are four goals of this project: (1) To examine the impact of different appointment reminder messages on appointment attendance; (2) to determine the added benefit of a patient navigator reaching out in advance of appointments to families at elevated risk of missing their appointment, and determine the most common barriers families face in appointment attendance; (3) to evaluate which patients are at highest risk of missing their appointment, and to determine the effectiveness of the intervention trial across different patient risk levels; and (4) to examine if the missing appointment interventions increase the socioeconomic diversity patients.

Aim 1: To test messaging strategies aimed at reducing missed appointments, via a randomized trial, across two different Kennedy Krieger outpatient clinics. Using the reminder system timeline and contact strategy already in effect in these two centers, the investigators will trial alternative language in the reminders (i.e., enhanced message #1 and enhanced message #2) against the current standard of care language. Hypothesis 1: Enhanced messaging will be superior to the standard of care in terms of reducing missed appointments. The investigators do not make a priori hypotheses regarding which enhanced messaging strategy will be optimal, given the exploratory nature.

Aim 2: To determine the added benefit of receiving patient navigation services for families at elevated risk of missing their appointment, and to understand the barriers to child neurodevelopmental evaluation appointments for the purposes of informing future interventions. Throughout the intervention trial, the patient navigator will continuously gather qualitative information on the barriers to appointment attendance faced by families identified to be at elevated risk of missing their evaluation appointment. Understanding these barriers will be critical to the development of future intervention efforts. Hypothesis 2a: Patient navigation services will be superior to enhanced or standard messaging alone in reducing missed appointments. Hypothesis 2b: Most families contacted by the patient navigator will face more than one barrier to attendance, and most barriers will fall into thematic categories that can be used to develop targeted interventions.

Aim 3: To examine the factors related to missed appointments. While the study team has previously identified families that are high-risk for missing their child's appointment, how those family and child-related factors replicate in a novel clinic is unknown. Hypothesis 3: The missing appointment factors will generally reproduce in an independent clinic, Center for Autism (n~3600 yearly diagnostic evaluation appointments), and generally reproduce in the updated data within Center for Neuropsychological and Psychological Assessment (n~6,200 yearly diagnostic evaluation appointments). This will allow the investigators to determine if the intervention is effective particularly for families at elevated risk of missing their appointment (Aim 4).

Aim 4: To examine if the missing appointment interventions increase the socioeconomic diversity of Kennedy Krieger patients. Previous research shows families from less advantaged socioeconomic backgrounds are more likely to miss their appointments. The goal of the intervention is to increase equity among Kennedy Krieger patients, rather than sacrificing equity at the expense of higher show rates (e.g., using punitive procedures). Hypothesis 4: More families at elevated risk of missing their appointments will attend their appointments when receiving the enhanced messages compared to standard messages, and further supported via patient navigation.

Inclusion Criteria:

• All patients who are scheduled to be seen within the center for autism or the center for neuropsychological and psychological assessment for evaluation appointments will be automatically enrolled in the reminder message portion of the intervention trial.
• Patients who are at elevated risk within the center for neuropsychological and psychological assessment are automatically enrolled in the patient navigator portion of the intervention trial.

Exclusion criteria:

• None for the messaging portion of the study
• For patient navigation, patients >18 years of age will be excluded.

Families and providers will be fully masked to condition. The investigators will know about condition as they orchestrate the study.