• by Karlene Lukovitz  @KLmarketdaily, November 12, 2015

Not surprisingly, at least in the short term, an E. coli outbreak that temporarily shut down 43 Chipotle stores in Oregon and Washington has driven down the restaurant brand's national consumer perception and purchase consideration scores, reports YouGov BrandIndex.

Chipotle's BrandIndex buzz score dropped from +4 on Oct. 30, just  before news of the E. coli illnesses broke, to -19 as of Nov. 9 — the brand's lowest buzz score since YouGov began tracking it in June 2007, according to the research company.

The buzz score asks respondents: “If you've heard anything about the brand in the last two weeks, through advertising, news or word of mouth, was it positive or negative?" A score of zero reflects equal positive and negative buzz; scores above zero indicate more positive than negative buzz; scores below zero indicate more negative than positive buzz.

On Oct. 31, Chipotle's daily purchase consideration score was 24% — meaning that 24% of all consumers 18 and older reported that they would consider purchasing from Chipotle the next time they wanted to buy fast casual food. After the E. coli news broke, it dropped to 19% by the middle of the first week in November, and has remained at about the same level since (18% as of November 11), reports YouGov. 

Chipotle’s previous 2015 purchase consideration low was 15% at the end of January, when the restaurant chain cut ties with a supplier that didn’t meet it standards, causing a pork shortage that lasted into the summer. YouGov says it began tracking the brand's purchase consideration score about two years ago.

YouGov BrandIndex interviews 4,300 people each weekday from a representative U.S. population sample, more than 1.5 million interviews per year. Respondents are drawn from an online panel of more than 2 million individuals.