First off, using online reviews isn’t an exact science. The purchaser is making a lot of assumptions. Additionally, it is nearly impossible to determine if the product is good if there are under 30 reviews. When you have very few reviews, there isn’t enough data to make any statistically significant decisions.
Look for “J” shaped distributions
Even if a lot of the top reviews are fake (lets say 50%), the distribution of reviews indicates that this is still a good product. On average, even if a lot of 5 star reviews are fake, the average number of positive reviews is above average. My conclusions align with the research in this article: “Statistics Unmask Phony Online Reviews”
Avoid a “U” shaped distribution
At first glance, a product can have an average review of 3 or 4 stars. This rating may make the product seem to have average reviews. However, if you assume that a large number of the positive reviews are fake, the average rating for this product falls significantly so that the opinion of the product could generally be considered “unfavorable”.
Assumption #1: 50% to 78% of positive online reviews are fake.
There are numerous articles about how businesses game online review systems.
Some people may assume that the number negative and positive reviews are equally fake essentially cancelling each other out. However, adding a positive review directly impacts the success of a product. Fake positive reviews seem to be systemic and primarily originate from business (or an affiliate of the business) that is selling the product.
A business could add a negative review to a competitor’s product. But, this action would only indirectly benefit the business leaving the negative review. More likely, fake negative reviews are left by individuals who do not like the business for other reasons and not by competitors.
Assumption #2: All bad reviews are horrible.
Consumers leave bad reviews for all sorts of stupid reasons. I would recommend clicking on the one star reviews in Amazon to better understand the problems other consumers are having. If some of the reviews seem trivial, then disregard them when making your decision. Additionally, a lot of 1 star reviews are helpful for finding alternatives, retailers with better pricing, and insight about product support.