Several Times a Year, OPEC Hosts Conferences among its Members to Agree on Further Oil Production Policies. OPEC Members’ Decisions Regarding Production Level of Cartel which Result an Increase, Cut or Maintain, Affect the Expectation of Crude Oil Price. Although for Consideration of OPEC’s Decisions in Regression Models Dummy Variables are used, Using Conventional Dummy Variables would only be Useful in Explaining Instant Effect of OPEC News Announcement. This Study Aimed to Access the Full Impact of OPEC News Announcement on Expectation of Crude Oil Price, Using Dummy Variables Modified by 4 Operators. The Results Indicate that Using Modified Dummy Variables in Comparison with Conventional ones, Lead to better Results and more Confirm the Impact of OPEC News Announcement on Expectation of Crude Oil Price.