Since Ranieri took charge, the Hornets have lost nine of 12 matches.
The aim was to stop the negative trend they had identified in performances and avoid a fight for survival.
The Pozzo family is known for their ruthless dealings with managers. Ranieri is their 10th appointment in seven years and his predecessor, Spaniard Xisco Munoz, was sacked with the Hornets 14th in the table having collected seven points from their opening seven games.
Following Saturday's draw with fellow strugglers, the Hornets are a point above the bottom three.
Since Ranieri came in, they've won two and lost 10 games, but their home game against Norwich on Friday is the most important of all of them.
With the postponement of Tuesday's trip to Burnley, and the fact that they will drop into the bottom half of the table if they lose to the Canaries, they face the Canaries knowing that defeat will see them drop into the bottom half of the table. They might be bottom by the end of the weekend.
How bad have things been under Ranieri?
Hornets fans were offered some hope last weekend when the team drew with Newcastle.
The form under Ranieri has not been great.
Since he took over, the Hornets have lost more games than any other team in the league and only three other managers in the history of the league have had a worse start.
All of the other managers who have been sacked by the Pozzos have had runs that were not as bad as Ranieri's current one.
No Pozzo-era manager has lost that many in their final 10 matches before leaving, with Javi Gracia, Walter Mazzarri and Marco Silva all departing after seven defeats in 10.
Leon Osman said on Radio 5 Live that if you want to get stability and improve, you have to have patience and give managers opportunities.
Ranieiri is only one game away from losing his job. What kind of message is being sent to the players? Is the players afraid of a manager? You don't need to because they won't be there long.
How come he is still in charge?
Ranieri's relationship with the owners could have earned him more time.
Ranieri knows exactly what to expect if the results don't improve because he has a long-standing friendship with the Pozzo family.
"I'm surprised he hasn't gone already," said Chris Sutton, a former premier league player. Watford made a mistake. The record of Ranieri has made him the only other manager in the history of the club to be fired.
They have been very ruthless in the past. Their gut instinct has been right to fire managers, but they aren't doing it this time even though the performances have not been good enough.
A mid-season dismissal by a struggling club is nothing new to Ranieri.
He was dismissed from his job as manager of the Cottagers after 106 days in charge, following a poor spell in which he won only three of 17 games.
He has had a bad run in England since the high point of his career, when he guidedLeicester City to their title triumph.
He lost 33 of 53 league games since that stunning success against all odds.
Rob Green is a former England goalkeeper. Look at how he runs his side. I don't think he is a good manager for modern players.
Micro-managing is what they need. He doesn't organize. I don't think he has lasted as long as he has with the model.
There is no hope of a revival.
While Ranieri has had a difficult time of it in England, he was in charge of two Italian sides before he moved to the UK.
The greatest hope is Ranieri's work at Sampdoria. He took over at the bottom of the league and led them to a 15th-place finish and survival.
The Hornets have not kept a clean sheet in 29 matches since February 2020 and have moved quickly in an attempt to solve their defensive issues.
There are some small signs of improvement under Ranieri.
Goals per game have crept up from 1 under Munoz to 1.3 under Ranieri and expected goals are up from 0.8 to 1.3 - so there is more attacking thrust.
The style of play has changed, with possession down slightly and more of an emphasis on pressuring opponents, with Ranieri's side winning the ball back in the final third 4.8 times a game on average, compared to 2.9 under Munoz.
The return of Dennis from injury is also noteworthy. The Nigerian player missed out on the Africa Cup of Nations due to an administrative error.
Dennis has eight goals and five assists in 17 games this season and seems to be crucial to the survival of the Hornets.
Ranieri said that he was not feeling the pressure. I am very professional with the club. I will continue with my strength and passion.
Ranieri was typically pragmatic when asked about the dismissal of Rafael Benitez. In Italy they change managers like they buy ice cream. That is it.