Intake's study to validate two portion size estimation methods with use of the Global Diet Quality Score (GDQS) app was recently published in the journal, Nutrients. The study assessed whether using the GDQS app with respondents reporting the amount consumed for each food group using a fixed set of 10 three-dimensional cubes of specified size; or with playdough was equivalent to the GDQS estimated by weighed food record (WFR) for the same 24 hour reference period. Results showed that using the GDQS app with cubes or playdough was equivalent to the WFR in assessing diet quality as measured by GDQS. The paper is available here.