Efficiency　is　a　relative　measure　that　allows　assessment　across　different　ranges.　Evaluating　the　performance　of　decision-making　units　(DMUs)　from　an　optimistic　perspective　yields　the　best　relative　efficiency　(optimistic　efficiency),　which　establishes　an　efficiency　frontier.　Conversely,　evaluating　from　a　pessimistic　perspective　produces　the　worst　relative　efficiency　(pessimistic　efficiency)　and　creates　an　inefficiency　frontier.　This　study　examines　the　efficiency　of　DMUs　in　two　scenarios　and　proposes　models　for　adjustment　coefficient.　The　pessimistic　and　optimistic　efficiencies　are　adjusted　to　the　lower　and　upper　bounds　of　the　DMUs　based　on　the　adjustment　coefficient,　enabling　determination　of　efficiency　intervals　for　all　DMUs,　as　well　as　evaluation　and　ranking.　A　Hurwicz　criterion-based　approach　is　introduced　and　applied　to　compare　and　rank　the　interval　efficiencies　of　DMUs.　Two　numerical　examples　are　examined　using　the　proposed　DEA　adjustment　coefficient　models　to　demonstrate　its　potential　application　and　validity.　　©　2024-IOS　Press.　All　rights　reserved.