Background: Using progress monitoring data to make effective and timely decisions in early intervention (EI) requires high quality assessment. Infant/toddler individual growth and development indicators (I/T IGDIs) have been developed to be brief, reliable and engaging progress monitoring tools that are sensitive to change over short time periods (Greenwood et al. in J Early Interv 33:254-267, 2011. https://doi.org/10.1177/1053815111428467). Objective: The current study examined the convergent validity of IGDIs in three developmental areas: the early communication indicator, early problem solving indicator (EPSI), and the early movement indicator (EMI), with standardized criterion measures. In addition, growth patterns in the current study of children receiving EI services were examined. Method: One hundred twenty-three children along with their service provider practitioners (N = 50) participated in the study. Practitioners administered IGDIs with children on their regular caseloads; data were examined for comparison with criterion measures and growth patterns. Results: Significant relationships were found between I/T IGDIs and corresponding domains on the Battelle Developmental Inventory-2nd edition and the Vineland Adaptive Behavior Scales-2nd edition. Linear and quadratic growth trajectory patterns from the current study resembled those of comparable samples from prior studies, where available. Conclusions: Results supported the convergent validity of these I/T IGDIs with established criterion measures. Growth trajectory patterns for key skills and total scores were similar to those in prior studies, where available, with a few exceptions. Growth trajectory patterns for the EPSI and EMI with children from EI programs were demonstrated for the first time and supported hypothesized patterns.