“When are you going to do the ‘70s?” asked a reader. I wasn’t planning to. After starting our calculations of the “lost factor” of various ‘80s hits with the year 1982, sort of a continuation of the late ‘70s with a lot of soft-pop holdovers, I was expecting that even the late ‘70s would be even more lost to time.

But when I decided to look at the Billboard Top 100 of 1978, I was surprised. The “lost factor” plots the trajectory between how big a song was at the time, and how many broadcast radio spins it got in North America last week, according to Nielsen BDSRadio. Unlike any year between 1980 and 1984, there were no 1978 songs getting no airplay at all that week.

If you’re looking for songs with a 1.0 “lost factor” or higher — our calculation of a song that is receiving airplay disproportionately low to its hit factor at the time — the number of such songs (44) is more comparable with 1982 (43) or 1989 (44) than 1984 (27). But if you’re looking for songs receiving fewer than 10 spins, there are only 10, compared with 26 for 1989, 23 for 1982, and even 12 for 1984. You haven’t heard much about the “long tail effect” recently, but it seems to keep a lot of 1978’s hits from disappearing entirely.

We’ve noted throughout that the resurgence of Soft AC (particularly the “Breeze” format) has kept some softer 1980s titles in play. But there’s also a new crew of even softer ACs, almost like the old “Music of Your Life” stations, led by WRME (Me-TV FM) Chicago, as well as a handful of stations like WHLI Long Island, N.Y., that actually evolved from ‘50s/’60s MOR to ‘70s gold. So even Barry Manilow’s “Can’t Smile Without You” managed 34 spins in the week we measured.

1978 was host to a few songs that remain key among the ‘70s that Classic Hits stations still play, even as they phase out the ‘70s to focus on the ‘80s and beyond. “We Will Rock You/We Are the Champions” by Queen and “Stayin’ Alive” by the Bee Gees, two late 1977 songs still anointed by radio, made the year-end countdown in 1978.

Then there’s Debby Boone’s “You Light Up My Life,” the song that wrapped up its fall ’77 domination of the Hot 100 as a cultural punchline and has mostly stayed there over the years. “You Light Up My Life” is a rarity. Many of the songs with the highest lost scores were songs that peaked in the lower reaches of the top 10 and get almost no airplay now. “You Light Up My Life” was the No. 3 song of 1978. It’s a big record that the audience chose to bury; even so, it got 16 spins for our airplay week. (If you’re wondering who still plays it, it’s mostly WHLI, WGVX (Love 105) Minneapolis, and KJUL Las Vegas.)

Here are the 15 “most lost” hits of 1978, based on points for their standing for the year divided by the number of plays they receive now. In parenthesis is the “lost factor,” followed by the number of spins the songs received in the U.S. and Canada according to NielsenBDS in the week prior to my calculations.

1. Shaun Cassidy, “Hey Deanie” (lost factor 33, spins last week 1)
2. Randy Newman, “Short People” (15, 4)
3. Toby Beau, “My Angel Baby” (10, 5)
4. Player, “This Time I’m in It for Love” (6,7)
5. Debby Boone, “You Light Up My Life” (6, 16)
6. High Inergy, “You Can’t Turn Me Off (In the Middle of Turning Me On)” (6, 2)
7. Andy Gibb, “(Love Is) Thicker Than Water” (6, 16)
8. Sweet, “Love Is Like Oxygen” (5, 15)
9. Peter Brown, “Dance With Me” (5, 14)
10. Raydio, “Jack and Jill” (5, 14)
11. Santa Esmeralda, “Don’t Let Me Be Misunderstood” (4, 5)
12. Andy Gibb, “An Everlasting Love” (4, 14)
13. Chic, “Dance Dance Dance (Yowsah, Yowsah, Yowsah)” (4, 21)
14. David Gates, “Goodbye Girl” (3, 18)
15. Chuck Mangione, “Feels So Good” (3, 29)

There are some recurring themes here that we’ve seen in our look at the ‘80s as well. One is teen idols. “Hey Deanie” was the Eric Carmen cover that even Shaun Cassidy’s detractors thought was surprisingly good at the time. Andy Gibb’s record of the year, “Shadow Dancing,” has a lost factor of 2.4 (about No. 22 most-lost for the year); not quite as abandoned as “You Light Up My Life” but surprising for a monster hit that now engenders more indifference than derision. Gibb endures at radio somewhat with “I Just Want to Be Your Everything” but shows up twice in the top 15 with other titles. Ray Parker Jr.’s career of hits-turned-snubs begins with his first hit, Raydio’s “Jack and Jill.”

One other odd aspect of 1978’s lost hits is that the top 15 contains more songs that I’m inclined to defend personally than many of the years we’ve looked at so far, although maybe that’s just a high-school junior’s nostalgia at work. I think that only caprice has made “I Love the Nightlife (Disco Round)” by Alicia Bridges surprisingly enduring over the years, while “Dance With Me” by Peter Brown faded. Or if it’s prog-pop you’re looking for, “South Park” exposed “Come Sail Away” by Styx as risible, once and for all, but it also gave it an odd aura of coolness that keeps it on the radio instead of “Love Is Like Oxygen” by the Sweet, the prog-pop opus that I like a lot better. But mine is clearly a minority opinion.

Conversely, these are the songs that punched above their weight with the most spins proportionate to their year-end placing. The songs listed here got their low “lost factor” numbers in a few different ways:

1. Bob Seger & Silver Bullet Band, “Hollywood Nights” (low year-end points, 369 spins)
2. Boston, “Don’t Look Back” (low year-end points, 395 spins)
3. Joe Walsh, “Life’s Been Good” (low year-end points, 453 spins)
4. Queen, “We Will Rock You/We Are the Champions” (high year-end points, but 2,257 spins; one of the most enduring of all classic hits, even before the “Bohemian Rhapsody” film)
5. Steely Dan, “Deacon Blues” (the No. 100 song of the year, but got 26 spins)
6. Styx, “Come Sail Away” (medium year-end points, 754 spins)

Having watched trends in music research for nearly 20 years, a lot of the late ‘70s warhorses like “Life’s Been Good” and “Come Sail Away” are starting to lose their footing, particularly at Classic Hits stations, but they remain solid B-level players at Classic Rock.

Songs like those, as well as Eddie Money’s “Baby Hold On” or Foreigner’s “Hot Blooded,” two songs with similarly low lost scores. also benefit from the greater number of available spins for pop/rock titles that can play at those two formats, plus Adult Hits. The least-lost R&B or pure pop title is actually Parliament’s “Flash Light,” which actually has a slightly lower lost factor than “Stayin’ Alive” on a combination of low-year end points and about 90 spins, mostly at Urban AC.

Next week, we wrap our look at the Lost Songs of the ‘80s with a special top 100 for the entire decade, as well as top 10 listings for each of the years we haven’t done yet, a look at “the making of” the lost ‘80s, and a few other surprises.