A pulmonary measurement system includes a pulmonary measurement device that includes a mouthpiece with an airflow path and a sensor positioned in the airflow path； and a controller communicably coupled to the sensor. The controller includes a processor and instructions stored in memory and is operable to execute the instructions with the processor to perform operations including identifying a measurement from the sensor； identifying a particular equation stored in the memory, the particular equation developed using data analytics and including an input parameter that is based on the identified measurement； and based on the identified measurement and the particular equation, determining a value of absolute lung volume.
