Illness perception (IP) is how individuals interpret a medical condition through their values, beliefs and experiences. In paediatric and neonatal intensive care settings, IP has been associated with parental stress, decision making and engagement with care. Differences in IP between clinicians and parents are common and can contribute to delays in decision making, moral distress and fractured communication. One difficulty with IP is that it can be misidentified as a substitute for understanding. Clinicians may worry that misaligned IP therefore means families do not understand the medical facts. If families are not emotionally responding to the medical information as clinicians expect or framing goals accordingly, clinicians may suspect they have not understood. But this incorrectly conflates IP with being informed about the medical circumstances. IP is, instead, how that information is interpreted, mediated by subjective experience and values and contributes differently to decision making than the facts alone. We propose an approach to decision making that incorporates IP as a distinct feature to explore. By engaging these differences directly, we posit that clinicians can more effectively support families, foster value-concordant decisions and navigate ethically complex medical decisions.