Tuesday, July 12, 2005

Ratings, Reviews & Tags

This post looks at some of the characteristics of ratings, reviews and tags before going on to consider the possibility of rating tags in order to enable the discovery of resources. It assumes raters share this objective, rather than the tagging of resources for other personal objectives.

So, in order to discuss the possibility of using tags as criteria against which to provide ratings information, I think I first need to outline what I see as some of the advantages and disadvantages of ratings, reviews and tags when compared to each other.

Ratings are relatively quick and easy to create. The information, whatever numerical scale is used (4-star, 5-star, Out of 10 etc.), is suitable for computational analysis. Ratings are often an assessment of "quality" against some ontological categorisation of the resource, particularly when an "overall" rating is provided. Alternatively some criteria may have been defined such as "price" or "ease of use" and once these criteria are understood by raters and users they provide more specific ratings information.

Reviews, on the other hand, tend to be more extensive and time consuming/difficult to write. They can provide a more comprehensive picture of a resource/product, but are far less suitable for computational analysis (e.g. collaborative filtering techniques). Users also tend to be less likely to provide a review than a rating due to the increased effort involved in writing them, which means there is less data about the resource available.

Tags, being relatively easy to create, look set to become popular. There is an implicit assumption that when a resource is tagged with a particular word, that word is considered to be appropriate for the resource - at least in the opinion of the tagger. Taggers often create a number of tags for a resource so it is probably more appropriate to consider a collection, or cloud, of tags here. In some respects this cloud of tags can be considered to be a highly stripped down review with all the grammatical stuff removed. Whilst this reduces (but does not eliminate) the suitability for human consumption it enhances the suitability for computational analysis. The free form nature of tags means there is little agreed ontological structure; this has its advantages (e.g. low creation costs) and disadvantages (e.g. no agreed definitions) as discussed by Clay Shirky in Ontology is Overrated: Categories, Links, and Tags.

So, having briefly considered the characteristics of ratings, reviews and tags, is there any benefit to using tags as rating criteria? Well, a couple of quick wins are that the minimal ontological categorisation overhead means they would be relatively easy to create as long as the associated rating format/code is also simple - see note below. The provision of an explicit rating also makes it clear that the rater/tagger is rating the resource against a criteria defined by the tag, as opposed to any other personal tagging objectives the tagger may have.

In terms of assessing rated tags against pure ratings, reviews or tags, I have been trying to find a way to visualise the different characteristics. One model is to consider the corners of a triangle as representing the characteristics I outlined above for a rating, a review and a tag. In this model a collection of tags, rather than a single tag, would be represented by a point along one side of the triangle away from the "tag" corner towards the "review" corner - as I think the collection of tags is moving towards becoming a stripped down type of review. If it is also assumed that when a resource is tagged an implicit rating is being provided then this point would move into the triangle - some way towards the rating corner. Finally, the provision of explicit ratings with each tag in the tag cloud would move the characteristics profile further towards the ratings corner of the triangle, as detailed ratings are being provided for each tag criteria.

That last paragraph may not have been so clear without a picture (sorry!), but my point is that a collection of tags with rating information has different characteristics to pure ratings, reviews or tag clouds. Such tag ratings are relatively easy to create, have some of the properties of a stripped down review, and are extremely suitable for computational analysis. They could also be highly distributed in nature if included in peoples' websites, or blogs, for example.

I would like to make it clear that I am not suggesting that all tags have an explicit rating provided with them. Tags without a rating can have a different meaning to the same tag with a rating - an "MP3" tag on its own indicates to me metadata about the resource, in this case that it is an MP3 file, while the tag "MP3" with a rating of 4 out of 5 indicates to me that against the qualities one may expect from an MP3 file (in terms of bitrate, lack of pops and distortions etc) in the opinion of the tagger/rater this resource scores 4 out of 5. I discussed this in my posting on 11 July 2005. Also, some other tags do not provide suitable rating criteria - again touched upon in that post.

In summary, the advantages (and disadvantages) of tagging (folksonomy), when compared to ontological categorisation schemes, can be transferred to rating mechanisms. The associated game for raters/taggers would be to capture the essence of a resource by selecting appropriate tags and rating the resource against each tag criteria. The objective would be to enable the discovery of such resources by others, more powerfully than ontological categorisation rating techniques, by combining rating, review and tag characteristics.

*Note: Representation of Rated Tag
One (completely unofficial and unauthorised) way to represent a rated tag would be to insert a rating into the rel="X" of a hyperlink as follows:
<a href="http://www.resource.net" rel="rating:4outof5">Tag</a>
It looks like a normal Tag and if the font size could be linked to the rating, higher ratings could be represented by larger tags which would result in a human readable representation as well. I'm still struggling to achieve this using the CSS style options!

Think that could give you some Search Engine popularity, and traffic???
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