Final answer:
An off-year election refers to a congressional election that takes place in the middle of a president's term, usually in even-numbered years. In contrast, a presidential election year is when the general election, including the selection of a president, occurs every four years. During a presidential election year, the president's party may experience a coattail effect, increasing the popularity of members of the same party running for Congress.
Step-by-step explanation:
An off-year election refers to a congressional election that takes place in the middle of a president's term, usually in even-numbered years. These elections are often referred to as midterm elections. In contrast, a presidential election year is when the general election, including the selection of a president, occurs every four years. During a presidential election year, the president's party may experience a coattail effect, increasing the popularity of members of the same party running for Congress. However, during an off-year election, the president's party is often blamed for the president's actions or inaction, which can lead to the loss of seats in Congress for the president's party.