I don't understand this mechanic... I have more Gain than Losses, so why is it so low?

Adding all the numbers gives your long term stability - the number to the right of the > .  In this case, 40+4+30-10-20=44.

Yeah, so how does a positive number have a negative effect on my stability. 

Wouldn't logic say that if I have more Gains in stability than Losses, my stability should be increasing?!

They aren't compared to each other.  They are all added together.  You don't have "increasing" stability.  The numbers show you have a long term stability level of 44.  Since your short term stability - the number to the left of the > - was 49, your stability is currently decreasing until it hits 44.

Ahhhhhh, I understand. Thank you for explaining this!

I have just downloaded the new DLC and getting back into the game (it is a great game, but very complex). 

Is this explained anywhere in the game? I feel like some of these important concepts are great, but not explained to the player in detail - and its definitively not common sense.

I could not find a simple explanation of this anywhere in the game.

So essentially, in layman terms, to have 100% stability, the total gains minus losses = the stability %... (this is not a percentage, its a result). 

If I were to subtract the value of all my Losses from my Gains, and that value were to be 100 or higher, the stability of the city would be 100%. 

Any value less than 100 will be reflected as a % value.. when in fact it is not a % of anything. It is just a number more than one. 

SimKlay wrote:

So essentially, in layman terms, to have 100% stability, the total gains minus losses = the stability %... (this is not a percentage, its a result). 

If I were to subtract the value of all my Losses from my Gains, and that value were to be 100 or higher, the stability of the city would be 100%. 

Any value less than 100 will be reflected as a % value.. when in fact it is not a % of anything. It is just a number more than one. 

1 - That is an essentially correct description.  It gives the long-term stability percentage.  The short-term/current stability percentage may be vastly different from that.  And it may take a long or short amount of turns to go from the short-term stability percentage to the long-term stability percentage, depending on a lot of other factors.  But that time is easily calculated from this screen - 1 turn in this case (49-5/turn=44 one turn later).  The percentage aspect isn't related to any of the numbers in comparison to each other, but affects bonuses and events that relate to that city.  Generally, having a city with a short-term stability percentage above 90 is good and having one below 30 is bad.

2 - Yes, again with the caveat that it is the long-term stability percentage

3 - Yes, the percentage doesn't matter on this screen (where it is just showing the math), it is used related to bonuses and events that relate to that city

I found the tutorials, pop ups, and screens like this decent in explaining the mechanics, but honestly a lot of it just became a lot clearer by playing.