To evaluate prices, we conducted a market-basket price survey. The market basket consisted of 152 items and included national-brand non-perishables and fresh produce, meat, and dairy products. Our price comparisons table show how each store’s prices compared to the average prices for national-brand and non-brand (fresh meat, produce, and dairy) items at sample stores from the area’s four largest chains: Albertsons, Fred Meyer, QFC, and Safeway. The survey was conducted from July 13 to 20, 2015.

The “Overall prices” tab of the price comparisons table shows how each store’s national brand non-perishables and fresh produce, meat, and dairy products stacked up. The $81 score for the Walmart Neighborhood Market in Bellevue shows that it was about 19 percent cheaper than the big-chain average for the same products. The $120 score for Ballard Market means that its prices were about 20 percent higher than the big-chain average. (Since the market basket includes fresh meat and produce, store-to-store quality differences may account for some price differences. Also, savings might vary depending on such factors as the extent to which shoppers take advantage of specials and coupons.)

For our survey, we used available sale prices and we assumed shoppers would use club cards at all stores that offered them.

The “Cheapest brands” tab of the price comparisons table shows the effect of substituting the cheapest available brand in each store for 26 national-brand items. WinCo, with a score of $79, beat the Kirkland Safeway’s prices by about 19 percent when we substituted the cheapest brands in place of some national brands at each store.

The “Variety” tab of the price comparisons table also shows the percent of market-basket items that our shoppers found at each store. For example, the Haggen in Woodinville carried 95 percent of the items in our full market basket that contains national brands.

To compare prices at Trader Joe’s with prices at conventional supermarkets, we used the modified survey described in the text of this article. Our section on comparing Trader Joe's prices describes this survey and shows the results of these comparisons.

We also used a modified survey to compare prices between conventional supermarkets and warehouse stores. Our section on warehouse stores reports those findings.

In our tab comparing stores’ Service quality, we report ratings we received from area consumers (primarily CHECKBOOK and Consumer Reports subscribers) of stores’ products and service. The survey asked respondents to rate supermarkets “inferior,” “adequate,” or “superior” on various aspects of quality, from “quality of fresh produce” to “convenience of store layout” to “overall quality.” Our ratings tables reports (for chains that received at least 10 ratings) the percentage of customers who rated it “superior” on each question.