Which of the following items is determined by the Date of Injury (DOI)?

The compensation rate for the worker's injury is significantly influenced by the Date of Injury (DOI), as it establishes the context for determining the benefits and entitlements available to the injured worker under workers' compensation laws. The DOI is critical in setting the applicable compensation rates based on the regulations and laws in effect at that specific time. Different rates may apply depending on economic conditions and legal statutes, which can change over time, making the DOI a fundamental factor in assessing the injury's compensation.

While the other options may also have relevance in the context of workers' compensation, they do not specifically hinge upon the DOI. For instance, the employer's financial obligations are governed by the overall statutory framework and agreements rather than being tied to a specific date. Similarly, the individual's choice of medical specialist might be subject to the insurance policy provisions or employer guidelines rather than the DOI itself. The worker's length of service could affect certain benefits and entitlements but is not directly determined by the DOI. Thus, the compensation rate directly corresponds to the Date of Injury, making it the correct answer.