There are two main law systems in the world: Common Law System and Civil Law System. Common Law System is established and developed from England, and most of the British colonized countries, such as Australia, New Zealand and a majority of states in USA inherited it. Civil Law System, on the contrary, came from France and Dutch. The main difference between these two Legal Systems is their trial methods, the adversary system is used in Common Law System and Civil Law System takes the inquisitorial system.
In simple words, the adversary system is a dispute; on the other hand, the inquisitorial system is an inquiry. For example, the judges' role is quite dissimilar in the two trial methods, under the adversary system, the judges act as a truth checker, his duty is to ascertain the evidence which provided by the parties, and according to the related law, make a decision beyond the ready evidence.
However, magistrates in the inquisitorial system have to get the evidence by themselves or from the appointed departments, to some extent, they have more power than the judges in the adversary system, they are able to control the whole trial method. As two trial methods exist in the same world, it can not be avoid being compared with each other, in my point of view, the adversary system is more efficient. The main advantage of the adversary system is its restriction of judges' power. As judges only need to go through the evidence provided, it limits the chance that the judges' own sensibility affect their judgment. Because of judges' own experience and status, sometimes they can't be helping having unfair view on something or someone; therefore, the restricted power of the judge could ensure the justice of the law. Another advantage of the adversary system of trial is the fact that there is recognition of the position of the defence / defendants .
Many of the rules in the adversary system are designed to favor the defence because the prosecution side has so many more advantages and financial resources. Judges in an adversarial system of trial tend to be more interested in ensuring the fair play of the trial, and they decide, often when called upon by counsel rather than in their own opinion, what evidence is to be admitted when there is a dispute. Many view the adversary system of trial as an advantage as the use of the jury in the common law system seems to have advanced the system by remaining the best way of providing for the determination of a disputed issue, again unlike the inquisitorial system having the judge with the final say. Basically on the whole the advantages of the adversary system is that there is minimized bias and prejudice on behalf of the judge and the defence are favored in that there is recognition of there position in the trial. Nevertheless, the adversary system also has some obvious disadvantage. One main disadvantage of the adversarial system is that adversarial justice is all about winning, winning with the limitations of rules about procedure and evidence.
Hence, justice might be replaced by victory. Another disadvantage is regarding the expertise of the judge. The court is not utilizing the expertise of the judge. In other words any questioning initiated by the judge should only be used for clarification purposes only. This restricted role of the judge is a product of convention thereby leaving the judges the inability to question witnesses on evidence not brought up in the case. The rich probably having the better legal service is also a disadvantage.
Due to the expensive fee in legal system, the poor is likely to lose the peer position to have the same legal service, which could cause injustice immediately. As mentioned before, to test the effectiveness of the adversary system of trial, advantages and disadvantages of the adversary system have to be taken into consideration. Therefore, as a result, the adversary system is effective in that it recognizes the defence's position and the likely bias and prejudice of the judge.