Thank you for asking me to review this paper reporting on the psychometric properties of the Stress Control Mindset Measure. Stress mindset and stress belief research is a burgeoning area with a deeper need for understanding the measurement of this new construct. As such, this paper reports on a timely topic. Despite this, I have several queries I would like to flag with the authors for further explanation and discussion, some of which may result in needing to make changes to the manuscript. I hope that these comments help the authors to strengthen their paper. Page numbers are based upon the author entered page numbers found in the top right corner of the document (with page 1 starting at the title page). First, I outline general comments followed by specific comments.

General comments:
1. Please provide PDFs of all output files so as not to restrict access to these based upon availability of software.

Specific comments:
Introduction:
Page 3, final paragraph: Kilby and Sherman (2016) found no relationship between stress mindset and threat appraisal. Please amend this paragraph to more correctly reflect the results of Kilby and Sherman (2016).

Page 4, final paragraph: Please provide more detail on how stress mindset - “beliefs about the consequences of stress” - is consistent with mindsets regarding the malleability of personality. Stress mindset does not assess the malleability of stress nor its consequences. I feel the argument that stress mindset involves beliefs of malleability of consequences a bit of a stretch. The beliefs surrounding stress mindset are not those of “negative stress can be used in positive or negative ways”, but rather the belief that experiencing stress (of an undisclosed nature, be it positive or negative) elicits either positive or negative outcomes. Crum et al (2013) proposed that stress-is-enhancing mindsets result in being “more likely to engage in actions that help meet the demand, value, or goal underlying the stressful situation”. To this extent, a stress-is-enhancing mindset is not about malleability of outcomes but rather about dispositional coping strategies. Further to this point, I wonder why the authors chose to focus on personality and intelligence mindset literature rather than the stress belief literature?

Page 5, final paragraph: Another possible explanation for the difference in wording could be that stress mindset is not a ‘mindset’ as described by Dweck but rather a set of beliefs, and therefore does not need to adhere to the fixed/malleable dichotomy of Dweck’s mindset. Indeed, Crum et al (2013) defined stress mindset as a pattern of beliefs with “stress mindset can be conceptualised as the extent to which one holds the belief that stress has enhancing consequences … or holds the belief that stress has debilitating consequences”.

Page 6, final paragraph: I cannot help but feel that this is a case of jingle and jangle in terminology in which a stress belief construct has been labelled as ‘mindset’ but has been conceptualised and operationalised as an explicit belief. Could the authors please provide a stronger justification for latching onto mindset theory as their driving theory rather than theories in belief and expectations?

Page 8, aim 3: Why was the SCMM not also compared to the Beliefs About Stress Scale which already contains a subscale specific to control?

Page 8, aim 4: It is unclear why trait challenge and threat appraisal are used in this study when the authors distinguished appraisals from stress mindset as being situation-specific. Should the authors not have used a situation-specific measure of challenge and threat appraisal? The use of a trait measure implies that appraisals are not purely situation specific, but rather may fluctuate slightly from their dispositional state based upon situational characteristics. If so, how does this then differ from stress mindset which also has a general ‘trait’ and specific ‘situation-specific’ measure? This is important given that the authors have distinguished appraisal from stress mindset on the basis that appraisals are situation specific but stress mindset is not.

Method:
Page 9, SCMM paragraph: What process was used to develop the 16 initial items? Why was the scales domains limited to only the four identified by Crum when many other areas of stress beliefs have been identified by other researchers? This question becomes more important when the Stress Mindset Measure was also constructed without consultation of the stress belief literature. Moreover, the example item stems (“you can use stress to…”) appear to highlight control over stress more so than malleability of stress (“you can change your stress”) per se. Malleability implies an ability to change or alter whereas control would imply an ability to utilise stress. If the authors are continuing with the Dweck perspective of mindsets, then this is an even more important distinction as Growth Mindsets imply one can change their intelligence (vs being able to ‘use’ their intelligence).

Pages 9 and 10: SMM measures: Why were both the general and specific forms used when this study did not present a specific stressor? Did these scales differ in score in any way?

Page 12, Trait cognitive appraisal style: Please make it clearer that this measure is being used to capture trait “stressor” appraisals.

Results:
Page 13: Factorial Validity: Why was the scale not subjected to an exploratory factor analysis first? This is generally considered a starting point in scale construction. Although there are theorised factors that are identified a priori which the items were drawn upon, that does not necessarily mean they are the most appropriate factors to use in terms of measurement. Moreover, this assumption asserts some rationale for these four factors being the factors. Given that Crum was unable to demonstrate a multi-dimensional factor structure, what evidence is there for forcing this proposed factor structure?

Page 17, Discriminant validity: What was the range of the 95% CIs? By taking the definitions of Bagozzi and Kimmel, then you may have also demonstrated Discriminant validity between the SCMM and the SMM. It is actually quite rare to ever find unity between any two measures. There are alternative approaches to defining discriminant validity other than a divergence from unity.

Discussion:
In general, the discussion does a good job of summarising the results. However, I am left asking myself the question “So how is this different to the SMM? What problem has this new scale solved?”. Yes, there is a slightly different wording of items, yes it explains a small amount of additional variance, but ultimately, the discussion is missing the ‘so what?’ factor. Why should stress belief researchers use the SCMM (which is nearly twice as long as the SMM) over the SMM to explain an additional 2-5% of variance?

Limitations:
Another limitation that has not been mentioned is the absence of external validity - that there is no behavioural demonstration of the scale’s functionality. Can the scale predict some aspect of the stress response of an actual currently lived stressor (rather than a past stressor considered in hindsight, which is susceptible to recall and hindsight biases)?

The authors should be congratulated on their efforts to reconcile the reviewer feedback. I believe they have addressed my comments appropriately and that the paper should be published.