Merging domains will sum the authority?

[Felip3]

Hi guys,

I have two websites that are almost the same, I am working to merge them. One domain have authority 44 and other 24... After I merge I will have authority 68?

Should I keep the older domain or the newer? The newer has my keyword in the URL but the older have 10 years.

Thank you

[EGOL]

One domain have authority 44 and other 24... After I merge I will have authority 68?

I doubt it.  I think that domain authority is closer to logarithmic rather than linear.... If I am correct, merging a DA 44 with a DA 24 might lift the DA 44 to 47 or 48.   Why?  A DA 24 is very weak compared to a DA 44.

Also, if the DA 24 has a lot of the same links that the DA 44 has then don't expect to gain much of anything in the rankings.   The best benefit will occur if the DA 24 has links and other quality signals that are totally different from the DA 44.  Then merging will bring fresh strength to the DA 44 - but again, a 24 is very weak and the benefit might only be worth a few points higher on the DA scale.