A score is more relevant than toss. Teams make their own luck. Toss only becomes relevant if the pitches & weather are in worse condition(yet its the skill of a team that determines result).
Toss factor works as unpredictable element, which in a way is good, as it poses a challenge for teams to show their various skills(bat or bowl)on alien conditions, or conditions which they are not comfortable with.
Predicting spin of a coin is the most difficult analysis, hence one should leave it to luck or unpredictable element.
Here are two stat piece processed from 106 Tests since 2011.
A ) Toss factor
|Batting||Mts||won||Loss||1st Inn >400 score|
|Bowling||Mts||won||Loss||1st Inn <300 score|
B ) Score factor
Batting: If teams are able to score > 400(1st Innings of a Test)than chances of not losing that Test is 92.42%. Here is a brief.
- Ø 400 score (1st Inn): 66 times
Loss: 5 ( 7.57%)
Draw : 23
If teams are able to restrict their opponent inside > 300 score(1st innings of a Test)than chances of not losing that Test match is 79.16%. Here is a brief.
- Ø 300 score (1st Inn) : 96 times
Loss: 20 ( 20.83%)
Runs(all kind) have to be earned by teams, and the ones who score the most win games. The challenge one hand is how to score runs, and on the other hand how to contain them!.
Toss is a uncontrollable factor, so is weather, and as far as pitch is concerned, it can be controlled by ICC. They can monitor watering of surface, mowing of grass, and keep vigil on regular patching on bowlers foot hole, popping crease, & other required places. This can be done every morning of a Test match.
All data processed before the 5th Ashes Test.