Epic geekery here.
I have a theory that an important factor in making a good album is to have a strong final third. So many albums start well but tail off towards the end. Sometimes this is because the artist doesn't really have enough good songs to make an album, and packs their two or three decent singles in the first 5 tracks.
I have analysed 145 of my albums to find out a few things. I mainly wanted to know the proportion of the albums that bucked the trend and finished well, and whether there were any patterns from any particular artists.
I did this by splitting albums in half and awarding a point to whichever half was strongest, and splitting albums into thirds and awarding three, two and one points for the strongest, middle and weakest thirds respectively. I only did this for albums that (a) had at least 9 tracks, and (b) I was confident I knew well enough to analyse well.
There were various problems with the method. It's hard to split an 11 track album into thirds, for example. Or, this gives no indication of how much better one section of an album is than another. But given the resources available (time, energy, inclination, knowledge, ability), it was the best I could do.
The findings? Of 145 albums, 120 had a stronger first half and only 25 had a stronger second half. The total points for thirds were: 1st third - 382; 2nd third - 259; 3rd third - 229. So the final third is not, on average, much weaker than the middle third - but the first third is definitely the strongest. And first halves are stronger about 80% of the time.
A total of 59 albums were 'perfectly front heavy' - that is, the first third was the strongest, the final third was the weakest, and the first half was stronger than the second. Only 6 albums were the opposite - first third weakest, final third strongest, second half stronger than the first. These six albums, if you are wondering, are Athlete - Beyond the Neighbourhood, Bottlerockit - Angel on a Vespa, British Sea Power - The Decline of British Sea Power, Coldplay - Viva la Vida or Death and all his Friends, Hurts - Happiness, and Lifehouse - No Name Face.
In terms of artists, I looked at any artist with three or more albums on the list, and looked for patterns.
Anberlin: consistently front heavy (i.e. strongest in the opening third), with weak middles.
Athlete: very varied, no pattern, each album is very different
Bloc Party: always front heavy, except for their best album, A Weekend in the City, which is back heavy
British Sea Power: same as Bloc Party - front heavy except for their best album which is back heavy
Casting Crowns: always perfectly front heavy and declining throughout the album
Coldplay: slightly varies but mostly front heavy
Delirious: generally front heavy, lots of weak middles
Enya: front heavy, except for her first two albums
Idlewild: very varied, like Athlete
The Killers: always front heavy
Lifehouse: front heavy except for their best album which is back heavy
Matt Redman: front heavy except for his best album
Mew: consistently front heavy
Muse: front heavy
Oasis: generally front heavy
Stellastarr*: front heavy with weak middles
Tim Hughes: front heavy
U2: front heavy
The pattern is pretty clear throughout: most albums are front heavy. Interestingly, there are several artists whose strongest album is the only one that is back heavy. Of the nine of my top ten albums of the decade for 2000-2009 that were in this analysis, only 1 had the final third as its weakest section, and 5 had it as the strongest section. It seems that, for me at least, a strong final third is an important factor in a good album.