The DALY does not reflect individuals' ability to cope with their functional limitations.
Estimations may exclude some disabilities, which leads to an underestimation of years lived with disability (e.g., childhood disabilities such as blindness or cognitive deficit), while some comorbidities might not be recognized (e.g., depression and substance abuse), leading to an overestimation or double-counting.
Improving DALY measurements will require better data collection and analysis. Specific improvements might include:
Validation of the methods to measure the time lived with disability of different severity;
More accurate monitoring systems to be able to generate real estimates of mortality and disability by cause; and
Projection methods that incorporate known levels and trends of major risk factors such as smoking and trends in other diseases.
The lack of data on psychiatric disorders in many countries has led to estimates based on methods that might not be transferable to assess the health status of the global poor. Further work is needed on standardizing assessment indicators to obtain a more realistic view of the burden of disease affecting developing countries.