The aim of this study was to assess the factorial structure of the scale, the method's effect associated with its negative items, its temporal invariance, and factorial invariance according to sex. For this purpose, three samples were collected, an initial sample of 200 participants, a second sample of 461 participants and a third sample of 107 participants; making a total of 768 Peruvian university students. Other instruments were applied together with the EROS scale in order to measure satisfaction with life, anxiety, stress and depression. Regarding the results, in the initial sample it was found that the original scale containing positive and negative items does adequately fit the data (RMSEA = .19; CFI = .77; TLI = .71) and also evidence was found supporting the existence of a methodological effect associated with the negative items. It was also found that version B of the scale which only has positive items data fits the data (RMSEA = .13; CFI = .96; TLI = .95). In the second sample it was found that version B still had a good fit to the data in a larger sample (RMSEA = .07; CFI = .98; TLI = .98). In addition, it was found that the scale can be considered invariant according to sex and presents validity based on other constructs. In the third sample it was found that the test-retest reliability of the scale was adequate (.70 [CI95% .593-.788]) and also evidence was found in favor of the temporal invariance of the scale. It is concluded that the scale formed only by positive items presents more robust psychometric properties and constitutes a better alternative to measure the level of reward provided by the environment.

中文翻译：

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环境奖励观察量表的心理测量特性：研究其内部结构、因素不变性和与负项相关的方法效应

本研究的目的是评估量表的因子结构、方法与其负面项目相关的效果、其时间不变性和按性别的因子不变性。为此目的，收集了三个样本，第一个样本为 200 名参与者，第二个样本为 461 名参与者，第三个样本为 107 名参与者；总共有 768 名秘鲁大学生。其他工具与 EROS 量表一起应用，以衡量对生活、焦虑、压力和抑郁的满意度。关于结果，在初始样本中发现包含正面和负面项目的原始量表确实充分拟合数据（RMSEA = .19；CFI = .77；TLI = .71），并且还发现证据支持存在与负面项目相关的方法论效应。还发现只有正面项目数据的量表版本 B 符合数据 (RMSEA = .13; CFI = .96; TLI = .95)。在第二个样本中，发现版本 B 仍然很好地拟合更大样本中的数据（RMSEA = .07；CFI = .98；TLI = .98）。此外，发现该量表可以根据性别被认为是不变的，并根据其他结构呈现有效性。在第三个样本中，我们发现量表的重测信度是足够的（0.70 [CI95% .593-.788]），并且还发现有证据支持量表的时间不变性。得出的结论是，仅由积极项目形成的量表呈现出更强大的心理测量特性，并且构成了衡量环境提供的奖励水平的更好替代方案。