How to compare ratings from different sites?

#1
Is there a formula that I can use to compare ratings from different sites? Let's say I am looking for someone to remodel a bathroom. If I search for bathroom remodelers, I find ratings from Yelp, Google, Houzz, Home Adviser, Angi, and others. Most of these give an Amazon-style 5-star rating and they disclose the number of ratings. Of course, not every contractor has a rating on every service.

So the data might look like this.



How can I calculate an overall rating? XYZ has the best rating, but there are only 2 of them and very few raters. Joe's and Jane's are close. Jane has a lot more ratings. ABC is all over the map.

I'd like to take into account the number of ratings as well as the actual ratings.

Any ideas?

Thanks
 

fed2

Active Member
#2
do you have access to the actual ratings (ie how many got each rating 1 to 5) or just mean/n. can you get stdev for each set?
 
#3
do you have access to the actual ratings (ie how many got each rating 1 to 5) or just mean/n. can you get stdev for each set?
No, unlike Amazon, which does display the distribution, most of these just provide the mean and n. And some of them don't even provide the mean, just the stars,m whioch look like they are rounded to the nearest 0.5 star.
 

fed2

Active Member
#4
do you have to use excel or do you have stats software?

How common is it for some sites not to have ratings for a given pair of contractors?
 
#5
do you have to use excel or do you have stats software?
I don't have any statistics software. I am willing to get one if it's (a) not too expensive and (b) not too difficult. I have taken a couple of statistics classes, but that was way back in the Roosevelt Administration (FDR, not Teddy ).

But Excel has a lot of statistics functions built in.

How common is it for some sites not to have ratings for a given pair of contractors?
I just compiled ratings from 5 different rating sites (Yelp, Houzz, BuildZoom, HomeAdvisor, and Google) on about 28 contractors. Of the 28, 1 was rated on 4 sites, 6 were rated on 2 sites, and the rest were rated on only 1 site.

Here's the rating table in I created in Excel. Column E contains the results of a little function I wrote to average the ratings. The 3 numbers are average rating, number of ratings (sites), and total number of reviews.