The 30-day trailing Consumer Sentiment Indices are computed at India and at the state level and for urban and for rural India. The survey design for estimation of 30-day trailing consumer sentiments Indices for India is based on the existence of 48 strata. The population is stratified at the State level and region-wise (rural and urban). Each of the 25 states sampled in our survey are further classified into Rural and Urban regions. Chandigarh comprises only one, the Urban stratum. Thus, we have a total of 48 strata.

In computing the Indices for the trailing 30-days, we consider all the households that are surveyed on that day and are accepted by an independent validation system on the same day. Both the conditions must be met for a household to be included in the calculation of 30 day-trailing Indices. Households that are surveyed on a day but are not accepted on the same day for any reason are not included in the computation of 30-day trailing Indices. If such households are cleared by the independent validation system on another day in the same month then they are included in the estimation of monthly Indices. But, they are not included in any 30-day trailing index estimation. Usually, 70 percent of the households surveyed on a particular day do get validated on the same day.

The weight assigned to each household for trailing 30-day estimations is calculated as the ratio of the estimated number of households on the day to the number of surveyed households in the trailing 30-days. For towns, it is the ratio of the estimated number of households in the urban region of the State in the trailing 30-days to the surveyed households in the urban region of the State in the trailing 30-days. And for villages, it is a ratio of the estimated number of households in the rural region of a State in the trailing 30-days to the surveyed households of the rural region of the State in the trailing 30-days.

The estimated number of households in the urban region of a State in the trailing 30-days is calculated by using the Compounded Annual Growth Rate (CARG) on the Census 2001-Census 2011 data for the urban households of the State, compounded on a daily basis. Similarly, estimated number of households in rural region for a State in the trailing 30-days is calculated by using the Compounded Annual Growth Rate (CARG) on the Census 2001-Census 2011 data for the rural households of the State, compounded on a daily basis.

Surveyed households in urban region of a State on a day are households that are surveyed and accepted on the same day for the trailing 30-days. Similarly, surveyed households in rural region of a State on a day are households that are surveyed and accepted on the same day for the trailing 30-days.

To calculate the indices, diffusion scores are obtained for each of the five questions. Diffusion score for each question is the percentage of households giving a favourable response minus the percentage of people giving an unfavourable response plus 100.

Calculation of diffusion scores for the jth stratum for the trailing 30-days:

Diffusion score for Question 1=

Diffusion Score for Question 2=

Diffusion Score for Question 3=

Diffusion Score for Question 4=

Diffusion Score for Question 5=

**CALCULATION OF FINAL INDICES FOR THE TRAILING 30-DAYS**
The index is calculated as a sum of the diffusion scores divided by the base period index for the total sample, multiplied by 100. The round ended in December 2015 has been chosen as the base period.

- Index of Consumer Sentiments(ICS)=
- Index of Current Economic Conditions(ICC)=
- Index of Consumer Expectations(ICE)=

The indices for urban and rural stratum are calculated in the same manner. However, the base period indices used are different.

For the calculation of indices for rural stratum, the base period indices are:

- Index of Consumer Sentiments(ICS) = 549
- Index of Current Economic Conditions(ICC) = 336
- Index of Consumer Expectations(ICE) = 213

The base period indices for the calculation of indices for the urban stratum are:

- Index of Consumer Sentiments(ICC) = 602
- Index of Current Economic Conditions(ICC) = 363
- Index of Consumer Expectations(ICE) = 239

Where

- = Diffusion score obtained for QUESTION_No_1 of the Consumer Sentiment Survey
- = Diffusion score obtained for QUESTION_No_2 of the Consumer Sentiment Survey
- = Diffusion score obtained for QUESTION_No_3 of the Consumer Sentiment Survey
- = Diffusion score obtained for QUESTION_No_4 of the Consumer Sentiment Survey
- = Diffusion score obtained for QUESTION_No_5 of the Consumer Sentiment Survey