Tried to look through and didn't see anything, so in case you folks aren't sure how the Oricon point system works, read on!
Combined Ranking System (Oricon's explanation; in Japanese)
Points are given based on different metrics:
1 CD or full single/album download: 1 pt
2.5 single song downloads: 1 pt
300 single song streams: 1 pt
1,440 album song streams: 1 pt
Streams does not include Spotify (or any service that allows free use, basically).
According to Oricon, CDs still make up just under 3/4s of sales at 73%, while streams/downloads make up the other 1/4 pretty evenly (streaming at 14%, downloads at 13%) as seen in the first half of 2018.
How did they get these numbers for downloads?
For
single sales, Oricon looked at every single in their charts for 2017 (5,503 singles) and averaged the amount of A-sides and coupling tracks. The average amount of new material (excluding instrumentals and remixes/lives) was 2.5 songs per single. Oricon also noted on average, people downloaded the lead track off a single versus the entire bundle/package, thus the need to differentiate “single track DLs” and “full single DLs.”
For example, if Hamasaki Ayumi released H now, chances are most people would only download independent versus downloading all three tracks. Since the average single has 2.5 songs, for every five downloads of independent, she would receive 2 points that can be added to her Combined Ranking total, regardless of the amount of downloads for July 1st and HANABI. That being said, the other songs would still count towards H's total sales.
How did they get these metrics for streaming?
According to Oricon's research, most paid streaming services average 2.1 yen per 1 play. If a single song is (on average) 250 yen, that roughly equals 120 plays. Taking the 2.5 songs per single as mentioned above:
2.5 songs per average single x 120 plays for a DL equivalent = 300 plays for a full single
This is how 300 plays = 1 single chart point.
Similarly for albums, using that same logic and analyzing the 4,482 albums that ranked, the average number of tracks per album was 12.
12 tracks per average album x 120 plays per song for a DL equivalent = 1,440 streams for 1 album chart point
Example:
Oricon lists an example at the bottom of the page, so let's take that example and apply Ayu's
H to it.
CD Sales: 5,428 singles sold. 1 single = 1 point, therefore she gets
5,428 points here.
Singular Downloads: Assuming
independent was downloaded 13,229 times,
July 1st 492 times, and
HANABI 302 times, this brings her total downloads for single tracks on
H to 14,023.
14,023 DLs ÷ 2.5 singular song DLs for one point = 5,610 points.
Bundle/Package Downloads: 125 times. Since the bundle counts the same as a CD single sale (1:1), she gets
125 points.
Streaming: Assuming
independent was streamed 847,392 times,
July 1st 59,403 times, and
HANABI 43,839 times, this brings her total streams for single tracks on
H to 950,634.
950,634 streams ÷ 300 streams for one point = 3,169 points.
Adding all the points together (5,428 points from CD sales + 5,610 points from singular song DLs + 125 points from bundle DLs + 3,169 points from streaming), her total for
H's combined ranking would be 14,332 points.
Oricon will label what platforms are being included (CD, DL, and/or St) in their Combined Rankings.
The downside to these combined rankings is
downloaded songs, even if they're Digital Singles (e.g. Together When...) still use the same formula of 2.5 DLs to 1 point. For example, although Yonezu Kenshi's
Umi no yuurei (so far a Digital-only Single) was downloaded 126,715 times (as noted in the week dated June 11th), he still received 50,686 points, placing him fourth in the combined rankings.