The threshold for determining whether someone is eligible for a publicly funded defense differs by state and jurisdiction and includes assets as well as the estimated cost of defending the crime. According to a 2010 census of public defense offices, the most comprehensive and recent source of data on this subject, about 80% of people charged with a felony are indigent. [1] Undocumented people accused of crimes are eligible for public defense in some states, including California. However, immigration courts usually do not have public defenders. Alameda County is a notable exception. 

 Yes. Public defenders represent only about 82% of indigent clients at the state and county level and 66% at the federal level. [2] Indigent clients can also be represented by attorneys contracted by the government for a period of time (contract-service systems) or private attorneys assigned by the government (assigned-counsel system). Evidence suggests that outcomes are much better for defendants who get a full-time public defender. [3]

Public defenders represent both felony (e.g., murder, rape, larceny) and misdemeanor (e.g., DUI, drug charges, petty theft) clients. States with capital punishment have specialized teams of capital public defenders who are usually funded at the state level. Public defenders only serve criminal defendants. In the US, defendants in civil suits (e.g., evictions, wrongful terminations) are not guaranteed a lawyer. Most of the public defenders we spoke with work either on misdemeanor or felony cases, but few specialize beyond that broad distinction.

Learn more about the flow of criminal cases for different crimes at this link.

Public defenders operate at various jurisdictional levels. Federal public defenders represent clients charged by federal prosecutors. In some states, public defenders are employed by the state and are stationed in offices throughout the state. In other places (e.g., California) public defenders are funded at the county and local level, and represent only clients charged with crimes in their area. This heterogeneity makes it more difficult to track down data about indigent defense and build tools to serve public defenders.

The American Bar Association recommends that public defenders who handle misdemeanor cases do not work more than 400 cases a year; [2] most misdemeanor defenders we spoke with worked on between 200 and 300 cases. The recommended caseload for felony defenders is less than 150 cases a year; most felony defenders we spoke with worked between 75 and 150 cases. Capital defenders work on far fewer cases, and usually less than ten. Unfortunately, in many places, public defenders end up needing to go over these limits.

Across the U.S. public defense system, 40% of cases are misdemeanors. [1] Misdemeanors may be less serious than some other crimes, but the consequences of misdemeanor charges can still be enormous. You might lose your immigration status, your kids, your job, and/or your housing. Regardless of the outcome of a case, some clients are still held in jail until the case is resolved. Resolving each case requires a significant amount of time, and many cases involve increasingly complex data.

• Every case includes at a minimum time-sensitive paperwork, several hearings, and police reports. In jurisdictions where police are required to wear body cameras, public defenders must review several hours of body camera footage.
• The majority of the caseload comprises DUIs, which include breathalyzer reports, blood samples, and calculations of blood alcohol level.
• Theft cases often include private surveillance videos which may require a proprietary player to view.  
• Social media and cell phone data are often relevant in harassment and assault cases.

The consequences of felony cases are high but variable, from a few years in prison to life. Typically, public defenders who work on felonies are somewhat more senior and work only on felony cases, although few specialize further.

Felony cases may involve:

• Anywhere from 6 to 100 hours of body camera video from different officers. Includes transport, witness interviews. May come as dozens of unlabeled and unsorted clips.
• Proprietary surveillance video which may require software to play
• Tracking down and interviewing new witnesses
• Tens of thousands of pages of social media data, usually as an unstructured PDF
• Digital forensics (Cellebrite) reports, often in unstructured PDFs or primary formats
• Ballistics, car black boxes
• Outputs of algorithmic systems (e.g., shot-spotter reports, automatic license plate readers)
• Forensics data and lab reports
• These cases are sometimes prosecuted through collaboration with multiple law enforcement agencies, such as local police and a gang task force or local police and federal law enforcement