1) Reasonable suspicion is the lowest standard. Most often used by law enforcement for car stops and "stop and frisk" searches.
2) Probable cause is higher than reasonable suspicion. Standard used by law enforcement to arrest after conducting a preliminary investigation, such as a DUI investigation. Probable cause issues often serve as the underlying defense in pre-trial motions.
3) Preponderance of the evidence is higher than probable cause. Standard used to determine whether someone violated probation by using alcohol or drugs.
4) Clear and convincing evidence is greater than probable cause but less than beyond a reasonable doubt. The standard used in civil cases and child custody disputes, where the state moves to remove a child from a home due to allegations of abuse.
5) Reasonable doubt is the highest standard. The standard applied in most criminal litigation and serves to afford the accused the presumption of innocence. This standard is what separates American Jurisprudence from other forms of criminal justice systems. The most important feature of our justice system is placing the burden of proof (and persuasion) on the government.