Furthermore, the rating of 8 would place a movie firmly in top 5% while the same 8 for a TV series barely cracks top 25%. In fact, a TV Series with 7.6 rating (like Grey’s Anatomy) places just above “Average” 50th percentile. Love Actually) to place in “Very Good”, a TV series must achieve rating of 8.4 to qualify for the same 90th percentile. The difference becomes even more meaningful when looking at the lower tiers “Very Good” (90th percentile) and below: while rating of 7.6 suffices for a movie (e.g. Going back to our example, 8.7 in TV Series places The Boys firmly in “Excellent” (95th percentile), while Goodfellas at 8.7 sits at the top of “Very Best” (99th percentile) in movies – noticeable difference between the two. Last piece of the puzzle is taking percentiles not across whole IMDb set but rather for each title type separately and compare them:
Feel free to assign and name percentiles differently in your analysis but we stick with this convention for this post. Following the same logic 99th percentile represents rating above 99% of all titles in the database (again, don’t forget about minimum threshold for number of votes to be considered).īased on above we can assign IMDb titles to groups based on the highest percentile they belong to: 99% percentile suggests that the title is very best, 95% – excellent, 90% – very good, 75% – good, 50% – average, and 25% – bad. In statistics such rating has a name: 100th percentile. Why? Because 100% of other titles are rated below or at best the same and that indicates exceptional qualities.
If a title has all time best rating then no doubt it’s worth giving a try (let’s say among titles with at least 1000 votes – number of votes is rather important consideration but we let it slide here and may come back to votes later). But how much different they are? (we will focus on fiction titles only from this point on.) Percentiles
So indeed ratings of movies and TV series come from different distributions representing different things like apples and oranges. Title ratings drift towards higher values depending on their types (shown on the right): movie, TV movie, TV mini series, and TV series.