However if a law is constantly changing, it will be quite difficult for individuals to understand their legal right and responsibilities. Frequent changes only lead to confusion in the community leading onto uncertainty and non-acceptance of that law. .
While on the other hand the law must recognise the changing values and needs of society. The law needs "Flexibility" in order to accommodate those changing demands. .
Inconsistencies in the law can lead to uncertainty about what the law should be or when the law applies which can lose the public respect for the legal system. The law may also be seen as being inconsistent if some individuals are treated differently to others. "Consistency" is desirable in most cases; the law needs to maintain some flexibility and discretion to take into account individual differences. .
For the law to be effective it must be able to be "Enforced". The legal system establishes a range of processes and institutions for the enforcement of the law. These include courts, prisons, adversary trial, jury system and the police. .
Changing values in society is in an ever state of change: the values that were upheld sixty years ago may no longer be relevant to today's society. For the law to function effectively it must provide a means by which laws can be changed.
We can judge whether a law is effective if it does what is stated above and goes out and proves it can still be consistent yet helping for the greater good in which ever form that may be. If those objectives or aim's add up once the law is in the system then only then can you claim a law was as effective as it said it would be.
I believe that all laws are for a purpose and are built around "social cohesion" for this very reason there hopefully is not an ineffective law. A law may be ineffective in other areas i.e. the Internet Censorship laws do not cover all topics which younger or older members of society might find offensive.