Reviewer response for version 1
This survey represents an important contribution to our understanding of career satisfaction among early career researchers. 
As you note, many efforts have focused on the US, so this study is especially valuable in light of its focus on the UK. 
However, the opt-in nature of the survey should be disclosed in the abstract, and several other parts of the manuscript could be productively modified.
Methods
- Please explain how the survey was advertised and what target audiences were likely reached.
- Since you have IP addresses, can you report how many of the responses came from within the UK and how many were from academic institutions? 
The former would be essential support for the claim that the report is representative of ECRs in the UK.
- Furthermore, can you compare age and other factors to any known statistics to evaluate how representative your sample is in these dimensions?
Results
- Please clarify whether the term “research” is used to mean academic research or research in industry as well. 
If the latter, did any of the survey respondents identify as industry researchers? 
For example, at the end of the section on PhD students, you write that 28% plan on leaving academia, yet the question asks about research - a very important distinction. 
Furthermore, I’m not sure that the fact that “only 28%” are planning on leaving is surprising, since the respondents did not provide information about their available alternatives.
- In the postdoc section, the statement “the large majority that didn’t feel comfortable in a future in research felt that they were working too hard” does not make sense at only a 33% response rate.
- Throughout, it would be helpful to provide the actual # of responses received, especially when discussing a fraction of a category (for example, X% of postdocs, etc).
Discussion
- Science can offer non-financial rewards, such as the pleasure of doing research and a relatively high level of respect. 
Therefore I suggest providing a caveat {indicated} to the sentence: 
“Working long hours and over weekends for relatively little {financial} reward”
- Regarding the statement “it is probable that some fraction of [researchers stating their intention to leave] will decide to remain, and the number who actually do leave may well be lower.” 
Rather than speculate, can you compare this to existing data on attrition rate, for example figure 1.6 from the 2010 Royal Society report “The Scientific Century” 1 ?
Figures
- Box 1-3: 
The colored bullet points are distracting - does the color code have meaning?
- Figure 1: 
This graphic is extremely difficult to read. 
Please label the pie chart sections directly (or better yet, make it a histogram) and provide axis titles and labels for all of the graphs. 
This will make the legends unnecessary. 
The “days per week” visualization would be much better represented by a distribution. 
PhD (which is ambiguous and should perhaps be PhD student), Postdoc, and PI labels are unnecessarily large.
- The data on comfort with long term prospects in research are very interesting. 
I would like to see a graphical representation of this as well.
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