In the 2017 BBL, it was found that the better the fielding side, the better the league position. We finally had proof that catches (and saves and run outs) win matches.

But does this apply to cricket outside the pros?

There was only one way to find out, and that is to try measuring the effect of fielding on a club team. So, during the 2017 UK summer, I have been keeping fielding impact scores for my team.

Spoiler alert: It turns out that the better the fielding side, the higher in the league you are. Here's how I came to that idea.

What is fielding impact?

The first problem was to work out how you measure fielding. I knew we had to get in catches, drops, stops, misfields, stumpings and throws for run outs. But how do you turn that into an easy to understand number of runs saved?

The very clever guys at CricViz came up with a measure called "Fielding Impact". Click here to read the details. I took the basic idea of assigning runs for each incident and adjusted the basic runs to reflect average scores in 50 over non-professional cricket.

Naturally, you could pick this method apart if you wanted. It is trying to make a prediction and predictions can never be totally right. However it seemed broadly fair in rewarding good fielding skills with runs saved, and punishing errors with runs lost. Over the course of a season, this will average out to a roughly correct ball-park figure.

Judging fielding

During our 50 over games, I then took the role of analyst: I recorded for both the team I coach and the opposition the following stats:

• Easy catch chances
• World-class catch chances
• Hit or miss stumps (and run out or not)
• Good stops and misfields
• Stumping chances

Naturally, some things are open to interpretation. A catch is a catch but was it expected or high-class? How do you tell the difference between a stop that saved runs and a stop that didn't? There is guesswork and cricket-knowledge involved. It's imperfect.

I feel strongly that as long as the analyst is consistent as possible, over time you will get a broadly accurate picture of how a team does in the field.

The results of fielding impact

Enough theory, what were the results?

The team I coach have played, so far in 2017, 10 matches. Here are the team scores (click to enlarge):

As you can see, there is a wide variation in impact. The overall impact for the team I coach is +64 (64 runs saved in total).

This compares favourably to the BBL scores where the best impact was +25 (in a shorter format).

Meanwhile, the opposition's impact is +15.

Currently the team I coach are top of the league, and so the fielding impact reflects the league position.

It's also now possible to say, despite dropping 17 catches in 10 games, this team hare have an overall positive fielding impact and are a good fielding side.

(Although as coach, the catch rate of 67% gives us something to work on.)

Mining the data

The other big advantage of having this fielding data is you can look for areas to work on.

For example, before this year I could not have said for sure where catches were begin taken and dropped. This year I can see easily that most catches are taken in the inner ring, we barely get a chance on the rope and we only take half our slip catches. I know what we are working on in training!

You can also see who is doing well individually. Here is a breakdown of impact per player in the team (click to enlarge):

From this information we can see who needs to do more practice in certain areas. The worst fielder by impact is one of the best fielders in the team, but he dropped four catches early in the season and has yet to recover from these expensive errors! Meanwhile the top fielder has not missed a chance.

Compare this to the traditional way of judging fielding: number of catches. A safe slip catcher and keeper will usually top the table but it hides things. For example, the player with the most catches in this team is only third in the impact table. The person in second place has only take one catch so far but has made a series of good stops, performed a run out and - crucially - not made a fielding error all year.

Is fielding impact worth it?

It's a lot more work to measure fielding impact, but if you are a team serious about getting better at fielding, you can use the information to better prepare.

If you can find someone to record fielding impact, go for it. It will be worth the effort when you take that league or cup winning catch!