Calculating Webcomic Growth and Attrition

Anyone want to join in? The goal is to figure out how fast the number of active webcomics is growing.

I recently reported that there seem to be about ten new webcomics appearing each day. This includes comics on sites like Comic Genesis. This is based on close personal observation and counting on both fingers and toes, but may be wrong. It would not be unreasonable to adjust that up or down by 50%. (Feel free to propose alternate figures where you see fit, just explain your reasons.)

If 10/day is accurate, that's 3650 new webcomics per year.

If all of them persist, as do existing webcomics, that means:

7,300/16,700 would be new titles after two years (under two years old)
9,950/ 20,350 would be new after three years (under three years old)

But of course, they don't all last.

Figuring out an attrition rate for all comics is best done by repeating the census from last fall that counted 9400 active webcomics. However, it would stall us for a year.

Dividing attrition between new and old is harder. It could be done by tracking "old" comic endings and deducting that from the total attrition. Or, a scouring of our active comic list could turn up attrition, though determining start dates is difficult. Complicating matters, many titles that have gone dormant recently have been culled already, and placed on a second list.

For now, let's take a guess. Let's say attrition affects 95% new and 5% old.

Without knowing how many comics end in a year, and how many new ones persevere, we are forced to guess.

If 10% of new comics last and 5% of old comics vanish:

954 vanish
365 last

That doesn't make sense because that suggests a shrinking total, but evidence points to a growing total.

I think the number for old comics ending may be too high.

If I change it to 1% of old comics vanish yearly, then:
365 new ones last
94 old ones vanish

Using those numbers, growth is about 250/year in the short term.

Does anyone want to argue for a different model, technique or variable? I'm not married to a conclusion and I welcome people's ideas. I think it would be useful for us as a profession to have a reasonable estimate of growth and attrition, and to develop a more polished analysis we can cite when writing about webcomics as a phenomenon or speaking to the media.

Don't worry about making a mistake. This is very much a "cocktail napkin outline." Someone will catch it and we'll gently mend it.