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I agree

Score going down despite posting new images

Bella123
18 Jan, 2020 00:46
Why has my score went down, when I uploaded more images, and received a lot of likes , and my score almost dropped by half! I don't understand the scoring system it seems when I upload new images and get likes my score dramatically goes down by almost half! Any answers to this would be appreciated.
Bella123
18 Jan, 2020 00:54
It seems like if I don't post images my score will not go down, to me this makes no sense, I actually don't care what my score is, I am here because I love Astrophotography, but it doesn't seem fair that the more images I post the lower my score gets   weird…..
Edited 18 Jan, 2020 02:59
ODRedwine
18 Jan, 2020 01:05
Your score is calculated from your average (perhaps mean) likes.  When you down load several images (7 by my count) they all start at 0 likes, so your score will go down.
jcoldrey
18 Jan, 2020 01:17
I believe that's correct Shawn, I recall Salvatore explaining roughly how it works in a few threads. It can help if you leave your old images in place also, which keeps your mean score down. Then a new image contributes positively to your index when its like match/exceeds your average score. The idea is trying to encourage/recognise folks getting progressively better at their imaging … so there is some logit behind it, which also encourages collaboration across the AstroBin community. Hope that helps a bit.
Bella123
18 Jan, 2020 03:02
Thanks for the information, I thought I was uploading really bad images! At least that's not the case
FerginFay
20 Jan, 2020 04:10
Naah Shawn your pictures are sick. I'll start liking them more  smile
ppbb
22 Jan, 2020 22:05
What is really bad that sometimes it's possible to decrease one's index by liking their photo.
Edited 22 Jan, 2020 22:06
Okke_Dillen
06 Feb, 2020 20:15
Paweł B
What is really bad that sometimes it's possible to decrease one's index by liking their photo.
just whitnessed this …. I find this confusing…. smile
carastro
07 Feb, 2020 14:10
I'm totally baffled with the whole index thing.  I am a very active member, liking posts, posting around 30 images a year, getting around 70 - 100 likes for each image, sometimes over 100. Have almost 300 followers and follow about 150 people.  Yet I am still way behind people who seem to be less active or get less likes.
It beats me what you have to do to get a high index.

Algorithms make no sense to me.

Carole
Edited 07 Feb, 2020 14:14
siovene
07 Feb, 2020 14:25
Please read this post to understand why it happens. I'm not saying it's Perfect or The Right Way, but this should at least explain.
carastro
07 Feb, 2020 20:21
I read that post previously and was even more confused as it made no sense to me.

I get this bit:
Say you have three images in total, with 10, 15 and 20 likes. The average number of likes is A=(10+15+20)/3=15

What is N?
What is a global average?

That's about as far as I understand it.
Perhaps I need a mathematical mind.

Carole
Edited 07 Feb, 2020 20:21
Die_Launische_Diva
07 Feb, 2020 21:56
At the time of posting a new image, the new image has zero likes. If the index was a simple average, that index would naturally drop. AstroBin's Index is a bit more elaborate than a simple average and handles this negative trend better. After some time the new image will receive a number of likes, hopefully at least near the average number of likes a person receives in the long term. But still this number is not known from the beginning. Each time the index is computed, it is not known if the current number of likes is the final number of likes the image will receive, thus is normal at an early state, the index computation to result in a lower index. By the way, why the index should always increase? What if I start posting nonsense images?

Well, I haven't a better way to explain this effect better. Frédéric has done a better job. Please take a look at his post and move on. As I have said in another post, the Index is a simple, clever, fair and forgiving measure of an astrophotographer's output. Trust me smile I have seen the code, re-implemented the algorithm and reproduced the AB index of several astroimagers from the top 100 list, and mine of course (BTW I'm still away from the top 100 thus I have no incentives to be supportive of the index LOL!)
Edited 07 Feb, 2020 22:03
Rich-sky
08 Feb, 2020 16:59
NA
Edited 09 Feb, 2020 23:22
siovene
08 Feb, 2020 17:18
That one is simple Rich: images with the last "action" are on top. Actions means they received a like, a bookmark, or a comment.
Okke_Dillen
08 Feb, 2020 18:49
Uhmmmm… whaaat??? smile

I think the relative humidity on the far side of the moon during carnival season devided by the remaining lifetime of Betelgeuse should be added to perfect the algorithm smile

smile
siovene
08 Feb, 2020 18:50
Careful what you wish for, Okke: I take user requests seriously! I might just implement that! April's fools day is close…
Die_Launische_Diva
08 Feb, 2020 21:53
I'm hearing that these days Betelgeuse has some troubles smilesmilesmile
Snjór
08 Feb, 2020 21:57
Betelgeuse variable just like Astrobin score!
frederic.auchere
09 Feb, 2020 04:08
Carastro
I read that post previously and was even more confused as it made no sense to me.I get this bit:
Say you have three images in total, with 10, 15 and 20 likes. The average number of likes is A=(10+15+20)/3=15

What is N?
What is a global average?

That's about as far as I understand it.
Perhaps I need a mathematical mind.

Carole

Hi Carole,

The index is computed with that formula:

I = log(N+1) x Average(likes >= A)

A being the average likes of all images (what I call in the post cited above the "gobal average" ), and N the number of images with numbers of likes greater or equal to A.

This may be a bit obscure if you're not versed in maths, so let me try with words, and let's forget about the logarithm term for now.
First, take the average number of likes of your 'N best images'. Your 'N best images' are those that have an above average number of likes (above or equal to be precise). So in the example above, the average is 15 and you have N=2 best images (those with 15 and 20 likes). Since the average number of likes of all your images changes each time one image is liked or when you upload a new image, the number N of 'best images' can change up or down. An the average number of likes of your best images can change up or down too. Fluctuations aside, that part of the formula measures the average number of likes of your above-average images, irrespective of how many images you have.

Now the logarithm term log(N+1) scales that average so that the more above-average images you have (and not simply the more images), the higher your index is. This bonus to quantity is however less and less rewarding as you make new images because of the logarithm. For example, In order to boost your inex by a factor 2, you would need to have 100 times more above-average images (because log(100)=2), and thus even more uploads (not all images are above-average).

Hope this helps you follow more easily the step by step example I gave.

CS

Frédéric
Edited 09 Feb, 2020 04:42
Okke_Dillen
09 Feb, 2020 14:34
Salvatore Iovene
Careful what you wish for, Okke: I take user requests seriously! I might just implement that! April's fools day is close…

smile

Great Salvatore, love to hear that! smile April 1st is coming! LOL smilesmilesmile

Die Launische Diva
I'm hearing that these days Betelgeuse has some troubles smilesmilesmile
I think the modern term is "burnout", a common desease these days, seems like stars are not excluded from that… kind of matches the situation Betelgeuse is in at this time… LOL smile
carastro
09 Feb, 2020 18:21
Frédéric Auchère
Hope this helps you follow more easily the step by step example I gave.
Thank you Frederic for taking the trouble to explain that, it is a little clearer.

I guess I only did Maths to O Level GCE.

So if I delete some of my early images which didn't get liked so much, (and it was early days of Astrobin with less people), am I right in thinking my global average would improve, and is this a good thing  for my index progression?

Carole
Edited 09 Feb, 2020 18:24
whwang
10 Feb, 2020 02:37
Carastro
So if I delete some of my early images which didn't get liked so much, (and it was early days of Astrobin with less people), am I right in thinking my global average would improve, and is this a good thing  for my index progression?Carole

Hi Carole,

Yes, it's a fast way to boost your index, much faster than adding excellent images.

That being said, I think your old images are all excellent.  Don't delete them just to get a higher index.
siovene
10 Feb, 2020 10:34
Wei-Hao Wang
Don't delete them just to get a higher index.
Agreed, that would totally be against the spirit of AstroBin.
Die_Launische_Diva
10 Feb, 2020 11:01
Carastro
So if I delete some of my early images which didn't get liked so much
That's sad. Consider all these people who admired, liked, and bookmarked those images. With all due respect, such practices discourage people from creating bonds with fellow hobbyists. Improvement comes from hard work, collaboration, and willingness to consider the opinions of others regarding our work.
carastro
10 Feb, 2020 13:42
Some of my really early images only had about 2 likes in one case zero.  If they are pulling my average down it seems pointless keeping them on the gallery.

If I move them to the staging area, but does the staging area count towards you average as well?  I have a fair few pictures on there that are non images.

Basically still trying to understand how it works and why some people seem to be high up in the index scale while others are not.

Carole
Edited 10 Feb, 2020 13:47
 
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