Book rating system by recommendations

[Molag]

Hi all. Can you please tell how I can make a rating system of books on recommendations. For example, I heard that Bill Gates recommended a book and Naval Ravicant recommended the same book. I add a Tag or something and give it, say, 5. Naval recommends the same book, so this book has a total of 10. Someone from the Internet - I give them a rating of 1. And the book begins to weigh 11. Can I do this on Calibre? Something like this

[Sirtel]

Hello and welcome to MobileRead!

You can create a custom column for this.

[JSWolf]

Can you explain how that sort of bizarre sounding rating system actually works?

[theducks]

Just how are you collecting the details of WHO rated WHAT in the first place???
What happens if someone I don't like rates the book. Auto delete the book??

[Molag]

Originally Posted by JSWolf

Can you explain how that sort of bizarre sounding rating system actually works?

Over the course of several years, an impressive list of books can accumulate that we have found interesting enough to put on our Wish List. Often different people mention the same books. There is a high probability that the books mentioned often are good books. The idea is that good books don't get lost in the big list. This is just one of the filters, it should not be blindly followed.

Originally Posted by theducks

Just how are you collecting the details of WHO rated WHAT in the first place???
What happens if someone I don't like rates the book. Auto delete the book??

I assign my own weight to the person, company, or course that had the reading list.

I've never thought about «if someone I don't like». But, if it's a professional in their field, I see no reason why you should limit yourself to learning something new. Or just ignore it.

For example, I want to understand the subject of Meditation, I filter the list of books and get a starter list from which to start familiarizing myself with the topic. In more detail, I can look at the books that were most often recommended.

[davidfor]

Without going to a potentially infinite number of rating columns (one per person/rating source) I can think of a couple of ways.

The simplest is a tag-like column. In that, you record a series of names that have given the thumbs up. Then the score is the total number of approvals.

But, I think I would do it with a tag-value. That would have a tag for who the rating came from, and a value for their rating. Then you average those ratings. Or you do something to weight the ratings based on the source and then calculate from there.

So, the value in a column for a book would look something like:

Bill Gates=4, Naval Ravicant=4, davidfor=1, Goodreads=3.9

Then you could create a template in another column that could calculate the overall rating from that. That could include a weighting for different sources (obviously, "davidfor" would have weighting of 0.001 and Goodreads would be a bit lower). And handle whether the number is out of five or ten or a simple thumbsup/thumbsdown.

I used an equals sign above as that is what I tend to use elsewhere for tag-value. But, it might work better to use a colon like an identifier. I'd have to look at the template functions to decide.

I would probably do it as a plugin with a predefined list of sources and the weights. Or a way to add them as needed. And then calculate the weights.

[capink]

As davidfor said, you will need a combination of a tag-like column + composite column:

• Create a new tag-like custom column called #recommendations. This column should contain the recommendations for the book. e.g Bill Gates, John ...
• Create a composite column called #score. Set the sorting of this column to numbers. Use the following template for this column:
  

  program:
      total = 0;
      default_score = 1;
      scores = 'Bill Gates:5,Naval Ravicant:10';
      for rec in '#recommendations':
          increment = ifempty(select(scores, rec), default_score);
          total = add(total, increment)
      rof;
      total

  This template should calculate the total score for you in the new composite column.
  
  Note that the line in blue is a comma separated pairs in the form of source:score. You must edit this to suit your needs. Every time you have a new source, you need to update this line in the template.
  
  The line in green is the score assigned to sources with no defined score e.g random people from the internet. Edit the value to suit your needs.

Note: You will need a recent version of calibre for this template to work. It uses a for loop which was introduced recently and not available on older versions.

Also note that the recommendations are case-sensitive. So: Bill Gates is not the same as bill gates.

[capink]

Or if you want weighted rating system as davidfor post suggests, discard the previous post and do this instead:

• Create a new tag-like custom column called #all_ratings. This column should contain the ratings from different sources as suggested by davidfor:
  

  Bill Gates=4, Naval Ravicant=4, Goodreads=3.9

• Create a composite column called #weighted_rating. Set the sorting of this column to numbers. Use the following template for this column:
  

  program:
      total = 0;
      cnt = 0;
      default_weight = 1;
      weights = 'Bill Gates:5,Naval Ravicant:10,Goodreads:1';
      for rec in '#all_ratings':
          source = re(rec,'(.+)=.+', '\1');
          rating = re(rec,'.+=(.+)', '\1');
          weight = ifempty(select(weights, source), default_weight);
          increment = multiply(rating, weight);
          total = add(total, increment);
          cnt = add(cnt, weight)
      rof;
      if cnt != 0 then
          divide(total, cnt)
      else
          '0'
      fi

  This template should calculate the a weighted rating for you in the new composite column.
  
  Note that the line in blue is a comma separated pairs in the form of source:weight. You must edit this to suit your needs. Every time you have a new source, you need to update this line in the template.
  
  The line in green is the weight assigned to sources with no defined weight e.g random people from the internet. Edit the value to suit your needs.

Note: You will need a recent version of calibre for this template to work. It uses a for loop which was introduced recently and not available on older versions.

Also note that the recommendations are case-sensitive. So: Bill Gates is not the same as bill gates.

[Molag]

capink, thank you, it works great.
davidfor, thank you for reply