Phased Transition To U.Mich Survey Collection Should Minimize Impact

We’ve seen some mention of the change in survey approach for the U.Mich consumer survey from phone to web interviews and whether it could be tied to the surprisingly sharp decline in today’s sentiment index from 77.2 to 67.4 in the preliminary May report. This from the data providers on the phased-in process which started last month (full here):

• “Starting with the preliminary release of April data, we will be supplementing the existing 600 targeted phone interviews per month with additional web interviews such that the monthly sample consists of 75% phone interviews and 25% web interviews. In May, half of the interviews will be collected via phone and half via web, and in June, 75% will be collected via web and 25% via phone. Starting with July’s preliminary release, all data will be collected via web, with a target sample size of about 900 to 1,000 interviews per month.”
• "This gradual transition smooths any differences between the two data collections across four months, ensures the continued integrity of the time series data, and is informed by over seven years of running a parallel data collection via the web alongside the official phone data collection. Our research shows that the Index of Consumer Sentiment exhibits a remarkably strong 0.97 time series correlation between the two data collection methods"