Impact (cause-effect relation) concerns research strategy, not the scale. Many papers that have "impact" or "influence" in title usually use the methods/research strategies (an experiment or longitudinal studies among others) that are relevant to investigate how one phenomenon influences another one . To investigate influence/impact, you have to: (1) check the covariableness (correlation, regression, chi square etc.) between variables, (2) control the time order in which the variables-values happen (in an experiment you can control the order, in a survey you can't) and (3) exclude the rival explanation (known from studying of the research history of particular problem) of the observed behaviour. In some papers about customer rating and buying intentions (which use surveys as the research strategy) you will find "the impact" or "the effect" in title and covariableness checked in the text only. You can't say anything about the direction of the impact (the rating causes behaviour ot the behaviour causes the rating) ) in question when you check the covariableness in your research only. There are two problems apart of your question: (1) what the firm's alternative actions&spending can influence the ratings and (2) does the customer behaviour influence the firm's performance (8 financial value drivers and finally NPV) or not. The research of ratings -> customer behaviour relation can explain only a part of the whole cause->effect chain. The question: how marketing contributes to supplier's NPV creation, is the most important problem in today-research.
Teng, L, Laroche, M and Zhu, H 2007, “The effect of multiple-ads and multiple-brands on consumer attitude and purchase behaviour”, Journal of Consumer Marketing, vol.24, no.1, pp.27-55
For validating your measure, I recommend the following article to read ...
Jarvis, C, Mackenzie, S and Podsakoff, P 2003, “A Critical Review of Construct Indicators and Measurement Model Misspecification in Marketing and Consumer Research”, Journal of Consumer Research, vol.30, no.2, pp.199-218
You need to measure consumer ratings (whatever they are) and purchase intention first. Then, you can estimate the impact of consumer ratings on purchase intention in a regression analysis by using consumer ratings as predictors (independent variables) and using purchase intention as a dependent variable.
I think you can use "shopping behavior" as a principal idea That you can adapt to your study according to a contextual analysis of the customer ratings in theexistant literature . Some examples :
A recent research study (Öğüt, & Onur Taş, 2012) investigated the impact of two service quality metrics (star rating and customer rating) on hotel room sales and prices. Two of the most popular tourist destinations in the world, Paris and London, are chosen. It is found that a higher customer rating significantly increases the online sales of hotels.
The study results show that a 1% increase in online customer rating increases Sales per Room up to 2.68% in Paris and up to 2.62% in London. Contrary to expectations, higher stars do not increase the sales. It is also shown that higher customer ratings result in higher prices of the hotel and the prices of high star hotels are more sensitive to online customer ratings!
Öğüt, H., & Onur Taş, B. K. (2012). The influence of internet customer reviews on the online sales and prices in hotel industry. Service Industries Journal, 32(2), 197-214.
I recommend Wright & Macrae (2007) for a validation of the use of the Juster scale as a proxy for future purchasing behaviour, and thus a good dependent variable for this kind of research. Also, see East, Hammond and Lomax (2008) for a prior example applying this scale to measure effects, similar to that which you wish to undertake. I have attached these articles for your convenience. Best wishes. Malcolm
Article Measuring the impact of positive and negative word of mouth ...
Article Bias and variability in purchase intention scales