Houllier has been encouraged by the youngsters who have filled the breach when up to a dozen players have been sidelined through illness or suspension.
But the former Liverpool boss is aware Villa have dropped 12 points in matches where they have been ahead during the current campaign.
This was highlighted a fortnight ago when Villa led Manchester United 2-0 after an exhilarating second half performance but ended up drawing 2-2.
Houllier said: "I'm confident, I trust this lot of players. But we have dropped 12 points from leading positions. That is a fact whether it was against Stoke, Bolton, Tottenham, Fulham or Manchester United.
"That is where we need to improve, definitely, in terms of maturity because being in a leading position to win, even if you drop half of those 12 points, we would now be on 23 points. I still think this is an area we have to address. Maybe this is the right time to stop that."