Thomas Frank's start to life as Spurs manager has been a mixed one.

They sit in ninth in the Premier League, but only Manchester City, Arsenal and Chelsea have scored more than their 20 goals so far this season.

These three teams are currently first, second and third in the table.

Some fans, though, have expressed concerns around Spurs’ attacking performances.

As the league's fourth best scoring side, such criticism may sound harsh, but is it justified?

Sunday's 4-1 drubbing at leaders Arsenal - as well as just one home win this term - certainly hasn't helped.

Here we take an in-depth look into Frank's tactics and how Spurs have created chances.

According to Opta, Spurs are fourth for goals scored but fourth from bottom in expected goals.

They have scored 20 times from an xG of 11.2, meaning they have scored about nine more than the average team would have, from the shots they have taken this season.

Arsenal, Manchester City and Chelsea have also over-performed their xG, but to a far lesser degree. When comparing the number of goals scored above their xG, Arsenal are at 2.7, City 2.0 and Chelsea 0.5.

This suggests the number of goals they are scoring is more sustainable over the course of a season than Tottenham's.

Spurs have the league's best shot conversion rate, but can they continue to be this clinical?

It is important to analyse their performances to understand if the data around their goalscoring form holds up.

To explain why Spurs have 20 goals despite getting into fewer dangerous shooting positions than their rivals, understanding Frank's tactics is the key.

The former Brentford manager's main tactic in attack is based on crosses into the box.

Using a right-footed and left-footed player on the same flank in Pedro Porro and Mohammed Kudus gives his side the option to play both inswinging and outswinging crosses.

Frank wants his players to play balls in from areas from which he believes they can be most effective - including out wide, from the half-space outside the box, or inside the box.

The third zone is often accessed by a central midfielder or full-back's underlapping run and allows for cutbacks to be played into dangerous areas.

In open play, Frank is essentially trying to create small-sided games in the wide areas, in which two or three players rotate and combine in order to create a yard of space for a cross into the box.

Following the cross, Frank wants his players to make runs into the box, arriving at the right time into the spaces between opposition defenders.

The Dane likes his teams to attack the box with numerous players to increase the likelihood of scoring from crosses.

Running down the line before putting the ball into the box also helps push the opposition deeper, which can open up space in front of the defence for attackers to exploit unmarked.

Shots from these situations have resulted in goals for Spurs, with both of Richarlison's efforts against Burnley coming from the Brazilian peeling off the last line.

One reason Frank prefers crosses is that it allows his sides to defend while attacking.

Rodrigo Bentancur and Joao Palhinha are usually positioned in central midfield positions behind the ball, while Spurs attempt to create crossing situations out wide.

If they lose the ball playing in wide areas it is less costly than losing it centrally.

If the ball is played centrally, both midfielders often opt to play safer passes, funnelling it out wide, ensuring possession isn't lost centrally.

The other ways Frank's men look to create chances are by counter-pressing to win the ball high up the pitch and maximising set-piece situations.

He describes pressing as an "attacking action" and wants his teams to press aggressively from the front.

Although they predominantly create chances out wide, Spurs have scored while attacking down the middle this season on occasion, but these goals have come after opponents lose the ball following pressure.

Their first goal at Leeds is a good example in which Spurs applied aggressive pressure to win a loose ball in midfield following a goal-kick.

With Leeds now in a disorganised shape, Tottenham were able to break quickly down the middle - resulting in a Mathys Tel goal.

Set-pieces are central to Frank's side as they were for old club Brentford. This season Spurs have scored six times from set-pieces, the fifth most in the league.

Their 3-0 win against Everton is perhaps the best example of their quality and reliance on them.

Frank's men ended the game with a lower xG than their opponents and 1.04 of their 1.72 xG came from set-pieces, with Spurs scoring twice from direct corners.

An unusual situation, though, from which his teams often score from, are in the second phases following set-pieces.

When a corner is cleared, Frank's sides quickly recycle the ball into wide areas. Opponents are unable to get out to these wide areas as quickly as they would when defending in open play, which allows crosses to be played with less pressure.

An added benefit to this scenario is the number of bodies in the box. Shortly after a corner, Spurs are likely to have numerous players in the area to attack the cross and therefore score, addressing Frank's concern around "attacking the last line".

Having explained how Frank wants his Spurs side to attack, we can now answer whether or not their goalscoring numbers accurately reflect how they've played.

Spurs have a concerningly low expected goals tally and this largely reflects the number of shots they have taken this season, with their 110 non-penalty shots the second fewest in the league - above only Burnley.

This tally is partly explained by their over-reliance on wide attacks, with crosses being harder to consistently find attackers in shooting positions cleanly. Only 24.2% of their attacks have come through the middle.

Frank stresses the importance of "attacking the last line" with numbers and timing, but has stated Spurs are only "OK" at it for now. An improvement here will naturally result in more crosses being converted into shots.

As chemistry develops between the wide players on each flank, their ability to combine quickly to create crossing angles in space should improve too. Integrating full-back Destiny Udogie, a natural left-footer, should help diversify Spurs' deliveries from the left.

This wide-first approach, however, is not enough on its own. It is too predictable against deep defences and back-five systems comfortable absorbing crosses and Spurs' lack of central creativity makes breaking down these blocks difficult.

With Palhinha and Bentancur prioritising rest defence, Spurs rarely create chances centrally when attacking a low block.

To score more often in games where they dominate the ball, Spurs will need to make use of their central attacking quality. Xavi Simons, the injured James Maddison and Dejan Kulusevski are all suited to operating between the lines and would add much-needed variety.

For now, Spurs play in a pragmatic manner. They are efficient and strong from throw-ins, corners and crosses. By preparing well, they turn these fine-margin situations into winning positions, before managing the game with less of the ball.

Spurs' attacks come in bursts rather than through long periods of possession and pressure, unlike Manchester City, Arsenal and Chelsea's approach, which helps explain the gap between their goals and expected goals.

Frank's attacking pillars will continue to produce goals, but the approach is somewhat predictable.

It is still early in his tenure but Spurs will need to improve their possession-based attacking plan, while retaining their current strengths, to sustain their goals scored.