The following appeared in a memorandum from the regional manager of the Taste of Italy restaurant chain After the first month of service the new restaurant in the Flatplains Mall which uses the Chipless brand of wine glasses has reported a far lower rate

Regional manager of the Taste of Italy restaurant chain has failed to convince us that all restaurants of the chain should switch from the Elegance brand to the Chipless brand of wine glasses. The argument, as it stands, is based on questionable assumptions and a faulty line of reasoning, a fact which renders it over-simplistic and unconvincing.

First of all, regarding the lower rate of breakage and taking into consideration that the restaurant in Flatplains Mall is a new one, it may have served fewer customers than the average of the restaurant chain. This ambiguous fact in turn, suggests that the time frame in which the data was sampled is too short, in contrast to the rest restaurants of the chain which may operate for a longer period of time. Thus, the report of lower rate may be unsustainable when comparing data based on different background, as it is possible that a longer period of time should be required to draw safer conclusions.

Next, the author states that employers frequently report that breakage is a result of the type of wineglass. However, there is not any statistical report regarding what portion of the total wine glass breakage is purely because of the glass type and not some other possible factor, like improper handling of the glasses due to dishwashing, accidents by customers' carelessness or something else. The author should have provided more information on how "frequently" should be correctly interpreted.

Furthermore, the author of the memorandum concludes that the restaurant chain should switch all of its glass assets to Chipless brand glasses since the customers of the Flaplains Mall restaurant seem to like it. However, the author does not provide any further information on how the sample of customers should be considered statistically valid. Were the customers asked to choose which glass is better between the two brands proposed in the argument or were they only exposed to Chipless brand wine glasses? Was the sample of customers asked large and diverse enough? The author should have provided more details about this point.

Last of all, the author does not inform us about the basis of the critical assumption that the restaurant chain will be financially capable to switch all of its glasses to the Chipless brand. No information is provided regarding how many restaurants are in the chain, how many of them have to undergo that change and what the total cost of the process will be. An appropriate reference to this point would significantly affect the strength of the argument.

To sum up, based on unsubstantiated assumptions and poor evidence, the author's reasoning does not provide concrete support for the stated conclusion. If the author had provided more information relating the rate and the actual numbers of breakage throughout the restaurant chain, a more solid justification of the customers' preference on the glass type and more financial data about the feasibility of the switch process, it would have been more thorough and convincing.