The Argentine manager has urged owners Todd Boehly and Behdad Eghbali to sign more players, despite spending nearly £400million in the summer.
The Boehly-Clearlake ownership have spent £1billion since buying Chelsea last year but the Blues are in the bottom half of the table after losing 2-0 at Everton.
Pochettino believes he lacks "aggressive" players and needs to bring in further reinforcements.
He said: "I think it's about to improve. We were talking after nearly four or five months, or 16 games, it's about to assess.
"We were not able today with all of the chances we had. We need to score if we want to win the game and we want to be in a different position in the table.
"It is not only to play, the team played well, dominated the game against a very difficult team like Everton.
"When you assess Everton, we deserve full credit because I think we were much better than them but in the end you need to score because if not, you build the confidence of the opponent and it is impossible to go 96 minutes without making a mistake.
"Then there's a massive assessment from the beginning of the season, from day one until today.
"When the transfer window opens, we will see what we can do. I will not say I need to ask for more players or less players but it's to see if the perception matches the reality. Is expectation here, reality here because we are missing something in the middle. That is the reality, maybe we need to improve our reality.
Chelsea were guilty of missing chances through Nicolas Jackson, Mykhailo Mudryk and Enzo Fernandez.
They were stung by goals from Abdoulaye Doucoure and Lewis Dobbin in a disappointing second-half collapse.