Environmental indicators are essential tools for tracking environmental progress, supporting policy evaluation and informing the public. Such indicators have gained in importance in many countries and in international fora. As part of their commitment to transparency and to better information of the public, OECD(ORGANISATION FOR ECONOMIC CO-OPERATION AND DEVELOPMENT)countries increasingly use a reduced number of indicators, so-called "key indicators", selected from larger sets to report on major environmental issues. The OECD pioneered the development of international environmental indicators and has long supported its member countries efforts in this field. Its work has led to several sets of environmental indicators, each responding to a specific purpose.

Factors such as information failures, technological externalities and market power can affect the prices, quantity, and quality of materials traded,  in addition, market barriers such as search and transaction costs can have an adverse effect on market development of recycling material. Ultimately, such market failures and barriers can even undermine the market entirely.

Criminal defense lawyers do much more than simply question witnesses in court. For example, defense lawyers:

• negotiate "deals" with prosecutors, often arranging for reduced charges and lesser sentencing
• formulate sentencing programs tailored to a client's specific needs, often helping defendants avoid future brushes with the criminal justice system
• help defendants cope with the feelings of fear, embarrassment and reduced self-esteem that criminal charges tend to produce in many people
• provide defendants with a reality check -- a knowledgeable, objective perspective on their situation and what is likely to happen should their cases go to trial.
• are familiar with important legal rules that people representing themselves would find almost impossible to locate on their own, because many criminal law rules are hidden away in court interpretations of federal and state conare familiar with local court customs and procedures that aren't written down anywhere stitutions
• understand the possible "hidden costs" of pleading guilty which a self-represented person might never think about
• spend time on a case that a defendant cannot afford to spend
• gather information from prosecution witnesses, who often fear people accused of crimes and therefore refuse to speak to people representing themselvesare
• familiar with local court customs and procedures that aren't written down anywhere

As criminal courts become ever more crowded, prosecutors and judges feel increased pressure to move cases quickly through the system. Trials can take days, weeks or sometimes months while guilty pleas can often be arranged in minutes. Also, the outcome of any given trial is usually unpredictable -- but a plea bargain provides both prosecution and defense with some control over the result.

In theory, a plea bargain may be negotiated at any time after arrest. In practice, however, the time to plead depends on the court and the jurisdiction -- some jurisdictions allow plea bargains only during certain phases of the criminal process. In many other places, however, plea bargains can be worked out virtually any time -- from shortly after the defendant is arrested (before the prosecutor files criminal charges) up to the time a verdict is reached -- even during trial itself. Also, if the trial results in a hung jury (the jurors are split and cannot make the unanimous decision required), the prosecution and defense may (and often do) negotiate a plea rather than go through yet another trial.