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.
