JWST proposals will be reviewed by panels of scientists from the international astronomical and planetary science communities that will make recommendations to the STScI Director, using well-defined Selection Criteria.

How STScI conducts the proposal review

JWST programs are selected through competitive peer review. A broad range of scientists from the international astronomical and planetary science community evaluate and rank all submitted proposals using a well-defined set of criteria and paying special attention to any potential conflicts of interest. The review panels and the Executive Committee constitute the Telescope Allocation Committee (TAC) that recommends the science program to the STScI Director. The STScI Director is the Selecting Official for JWST. Based on the recommendations, the Director will make the final allocation of observing time. Full details on the peer review process are given in the JWST Peer Review Guide. 

The Review Panels

Dependent on their size and type, proposals in JWST Cycle 5 will be reviewed either by external panels or by discussion-based review panels.

Discussion panels

The Cycle 5 discussion-based (i.e., synchronous, but virtual) review is planned to comprise seventeen topical panels:

• one Solar System;
• three Exoplanet Atmospheres and Habitability;
• two Exoplanetary System Formation and Dynamics;
• two Stars and Stellar Populations;
• two Gas, Dust, and the ISM;
• two Nearby Galaxies to Cosmic Noon;
• three High-Redshift Galaxies and the Distant Universe;
• two Super Massive Black Holes and Active Galaxies.

The science topics covered by each panel are listed in the Appendix - Science Keywords. Where there are multiple panels, each panel covers the full range of science topics within that science area.

A high-level description of topical coverage in each panel is given in the following table:

Proposers should note the breadth of topics covered within each science area. Each proposal is read by multiple reviewers. For the topical panels, all reviewers will have expertise within the broad science area. Few, or even none, may have expertise in the specific subfield of the proposal. For the Executive Committees, all reviewers will have expertise with the field of Galactic or Extragalactic astronomy, but few will have expertise within the broad science area of the proposal, and it is possible none will have expertise in the specific subfield of the proposal. Proposers should take care to write for an appropriately broad audience.

Each panel will be managed by a Panel Chair and Vice Chair, and there will be two TAC chairs overseeing the review process, one for the Galactic panels and one for the Extragalactic panels. Panelists are chosen based on their expertise in one or more of the areas under review by the panels. The Discussion Panels assess and grade Small (> 20 and ≤ 50 hours) and Medium (> 50 and ≤ 130 hours) GO proposals and all Target of Opportunity and Survey proposals, regardless of size. The time allocated to each panel is proportional to the time requested by the proposals assigned to that panel; there are separate allocations for Small and Medium proposals. Discussion Panels do not adjudicate Large (>130 hours) GO proposals, Treasury GO proposals, AR Legacy proposals, or Pure Parallel proposals, but they will advise their chair on the scientific merit of the subset of those proposals assigned to their panel.

External panels

The Very Small GO proposals (≤ 20 hours) and all regular AR proposals will be distributed for external review. Those proposals will be assessed by five experts who will grade on an absolute scale against the primary criteria, as discussed below. External Panels are chosen based on their expertise in one or more of the scientific topics covered by the panel. Each external panelist will receive a limited number of proposals. The proposals will be grouped by subject area, following the same Science Categories used for the Discussion Panels. The proposals likely to be recommended to the Director for acceptance will be provided to the Panel Chairs of the face-to-face Discussion Panels of the corresponding Scientific Category prior to the meeting to allow them to identify potential duplications with the proposals reviewed by their panels. 

The Executive Committee

As in Cycle 4, the Cycle 5 EC review will be split into two parts: Galactic EC and Extragalactic EC. Each of the two Executive Committees will include a TAC Chair and the Chairs and Vice Chairs from all the corresponding topical panels. The primary responsibility of the ECs is to review Large GO proposals (> 130 hours), all Treasury GO programs, Legacy AR programs, and all Pure Parallel programs. The ECs are provided additional input on proposals through feedback from the discussion panels via the Panel Chair and Vice Chair.  

Selection criteria

Primary criteria for all proposals

Evaluations of JWST proposals are based on the following three primary criteria. Each criterion is given a separate grade, then the grades are combined with equal weight. Reviewers will be instructed to evaluate these criteria based on what is written in the proposal.

(A) In-field Impact:

• The scientific merit of the program within its immediate sub-field, and its contribution to advancement of knowledge.
• The immediate sub-field of the proposal is the niche area of the program, not the whole broad science area (e.g. Trans-Neptunian Objects, not Solar System Astronomy).
• Proposals should address how the proposed program will improve understanding of the objects, classes of object, or specialist topics under study, and why the work is relevant and timely.

(B) Out-of-field Impact:

• The program’s impact outside of its immediate sub-field.
• A proposal does not have to impact all of astronomy. The out-of-field impacts could be in other sub-fields within the broader science area of the proposal, or in other broad science areas (e.g. in the case of a TNO proposal, this could be solar system formation or planet formation in general, among others).
• Proposals should discuss implications for other fields or sub-fields, and their breadth, significance, and timeliness.

(C) Suitability & Feasibility:

• The suitability of JWST observations or datasets, or relevance to JWST science. The necessity of special requirements. The feasibility of the science program.
• Proposals should demonstrate that the capabilities of JWST are required to achieve the scientific goals, or demonstrate the relevance of the work to JWST science. Technical issues will be adjudicated by STScI instrument scientists.
• Proposals should include a clear observing or analysis plan that demonstrates a clear path to science. Proposals should justify time requests and any special requirements, including duplications or joint observatory time.

Further information on the grading rubric, including example cases, are included in the Selection Criteria and Scoring System guide. 

Additional criteria by proposal type

Additional criteria exist as well, depending on the Proposal Category, as listed below. Letters in square brackets indicate the affected Primary Criteria.

All GO Proposals

• The rationale for selecting the type and number of targets: Reviewers will be instructed to recommend or reject proposals as they are and to refrain from object or hour trimming. Therefore, it is very important to strongly justify both the selection and the number of targets in your proposal, as well as the number of hours requested. [C]
• The reasonability of requested resources. [C] 
• The extent to which experimental or supporting ground-based observations support the science goals of the proposal. [A,B]

Large GO

• The level of coordination of the overall work described and the production of appropriate data products and/or tools. [C]
• The utility of the higher-level data products and/or tools. [A,B]

Treasury GO

• The level of coordination of the overall work described and the production of appropriate data products and/or tools. [C]
• The utility of the higher-level data products and/or tools. [A,B]
• The extent to which the data products will enable additional scientific investigations and the importance of those investigations. [A,B]
• The level of data products produced and plans for their timely dissemination to the community. High-level science-ready data products should be made available through the MAST data archive or related channels. [C]

Calibration GO

• The extent to which these observations or analyses enable new types of scientific investigations with JWST and the importance of those observations. [A,B]

Joint Programs

• The extent to which the proposed observations with the Partner Observatory (ALMA, Chandra, HST, NASA-Keck, NOIRLab, NRAO, TESS and/or XMM-Newton) are critical for the science goals of the proposal. [C]

All Survey Proposals

• The TAC will evaluate the science within the context of the optimal number of targets and minimum number of targets indicated in the Special Requirements Section of the proposal. [C]

All AR Proposals

• The improvement or addition of scientific knowledge with respect to the original use of the data. In particular, a strong justification must be given to reanalyze data if the new project has the same science goals as the original proposal. [A,B]
• A well-developed analysis plan describing how the scientific objectives will be realized. [C]

Legacy AR

• The level of coordination of the overall work described and the production of appropriate data products and/or tools. [C]
• The utility of the high-level science-ready data products and/or tools. [A,B]
• The extent to which the data products will enable additional scientific investigations and the importance of those investigations. [A,B]
• The level of data products produced and plans for their timely dissemination to the community. High-level science-ready data products should be made available through the MAST data archive or related channels. [C]

Calibration AR

• The extent to which these observations or analyses enable new types of scientific investigations with JWST and the importance of those analyses. [A,B]

AR Theory

• The extent and importance of JWST science investigations enabled by the theoretical analysis and results. [A,B,C] 
• The level of planning for timely dissemination of theoretical results, and possibly software or tools, to the community. [C]

AR Cloud Computing Studies

• The relevance of the proposed AR Cloud Computing Studies to JWST science investigations and/or data reduction or interpretation. [A,B,C]

AR Data Science Software

• The relevance of the proposed software development to JWST science investigations and/or data reduction or interpretation. [A,B,C]
• The level of planning for timely dissemination of the proposed software products to the community. [C]

Recommendations for acceptance

The task of each panel is to provide a rank-ordered list of proposals. Each panel is allocated a pool of Hours based on the submitted time pressure. Proposals are recommended for acceptance in rank order until the pool of Hours allocated to the panel is exhausted. The allocation is typically N and the cut-off in ranking is called the 1-N line.

Some proposals do not request prime observing hours, including AR, Survey, and Pure Parallel. These programs, together with Calibration programs, cost Zero Hours to the panel, however, they are expensive in other resources. As such, all proposals in a panel are ranked together based on their scientific merit, and Zero-Hour proposals are required to rank competitively with the other accepted programs. That is, only programs ranked above the 1-N line are recommended for acceptance, regardless of their Hour cost.

There are further restrictions on some proposals that are considered across all panels together, such as Disruptive ToO activations or Survey targets. For these, first only proposals above the 1-N line in their panel are recommended for acceptance. Then, if the set of all recommended proposals exceed the allowed activations or targets, the panel rankings are used to further down-select proposals until the activation or target limits are not exceeded.

Next: JWST Guidelines and Checklist for Proposal Preparation