That is the definition of the word improvement according to Wiktionary. Investing in HYIP is like that. In case you got scammed, you just need to move forward and at least know the reason why the program failed. Maybe because It's been running for too long when you joined, or maybe there are no new members where they can get the payment for old members. What ever the reason, you at least have an idea what to do in your next investment. What important is to learn from our mistake or learn from the mistakes of others.
The act of improving; advancement or growth; promotion in desirable qualities; progress toward what is better; melioration; as, the improvement of the mind, of land, roads, etc.
Maybe when you got scammed you're scared to invest more money. I don't think that's the right attitude when investing in HYIPs. Earning in HYIPs is fluctuating. Sometimes there's a gain and sometimes there's a loss.
Don't put all your eggs in one basket.It is important to pick several high potential looking programs and put small amount on each to minimize risk. So even if one or two program failed you still have several other programs to cover the loss. On the average you'll be on a gain. Don't dedicate all your resources into one thing.
ciao!
J.Chris