There are also an entire series of attitudinal questions regarding why this specific restaurant was chosen, and these could range from convenience for a family meal together, or for a special occasion. Clearly expectations are significantly higher for those respondents going out to dinner for an anniversary, birthday, or significant family event - all instances were respondents would be going to more upscale restaurants.

There is the entire price/quality aspect of this research. It is one experience to dine at McDonalds' or Burger King and have the expectation of the burger and fries tasting like they have in the past, and quite another to eat at a local 4-star restaurant where patrons would expect highly personalized service and an attentive waiter or waitress during the dining experience....

In short, there are major environmental variables that need to also be taken into account, specifically in the area of price and quality expectations. In summary the demographic and psychographic attributes of respondents and the entire ritual of dining out as it relates to si9gnificant life events also needs to be studied to further understand how the mere look on someone's face can be seen as a predictor of the tip they will leave. An entirely other area of research also needs to be the attitudes and perceptions of the waiters and waitresses; a member of the NHF group may actually receive better service as the waiter or waitress may think the lack of a smile is intended for them. Internalizing the expression on a customers' face may actually deliver greater service, which is a fascinating area for future research as well.
References

ResearchMethods (2007) - Web Center for Social Research Methods. Research Methods Knowledge Base. Accessed from the Internet on July 11, 2007 from location: http://www.socialresearchmethods.net/kb/measlevl.php

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