SUTRA Model: Eyebrows raised
Scientist have raised questions on the government-backed model, called SUTRA, to forecast the rise and ebb of the COVID-19 pandemic. Scientists believe that the model may have played a major role in creating the perception that a second wave of the pandemic was unlikely in India.
SUTRA stands for ‘Susceptible, Undetected, Tested (positive), and Removed Approach’
Developments and Details
- The scientists from the Indian Institute of Technology in Kanpur and Hyderabad have applied this model to predict the peak of COVID-19 cases.
- SUTRA model uses three main parameters to predict the course of the pandemic: Beta or Contact rate: It measures how many people an infected person infects per day. It is related to the R-nought value, which is the number of people an infected person spreads the virus to over the course of their infection.
- Reach: It is a measure of the exposure level of the population to the pandemic Epsilon: It is the ratio of detected and undetected cases.
Issues with SUTRA
- Many instances of the SUTRA forecasts being far out of bounds of the actual caseload (National Centre for Biological Science)
- The predictions of the SUTRA model are too variable to guide government policy.
- Relies on too many parameters and Recalibration done whenever the predictions are different
- The SUTRA model’s omission of the importance of the behaviour of the virus
- New variants showed up in the SUTRA model as an increase in value of parameters called ‘beta’ (that estimated contact rate).
- As far as the model is concerned, it is observing changes in parameter values. It does not care about what is the reason behind the change