Overview - Cycle 1

The James Webb Space Telescope (JWST) science peer review process is organized by the Science Policy Group (SPG) of the Science Mission Office (SMO) at the Space Telescope Science Institute (STScI).

Requesting help

Please contact the JWST Help Desk (https://jwsthelp.stsci.edu) for any questions that you may have, including questions about science policy or technical performance. In your correspondence, please identify yourself as a Telescope Allocation Committee (TAC) member. If your question is about a specific proposal, please state the ID for the proposal associated with your question.

Proposal types

JWST proposals are of three main types:

  • General Observer (GO) proposals request observing time in hours. GO proposals are classified as Small (1-25 hours), Medium (>25-75 hours), or Large (>75 hours). 
  • Survey programs use small amounts of otherwise idle time in the JWST schedule; they are allocated a number of targets of which in practice only a fraction, ~30 - 70%, will actually be observed.
  • Archival Research (AR) programs are to carry out investigations using the JWST Archive and are awarded a dollar amount (proposers from U.S. institutions only).

GO proposals include Long-Term proposals, Joint HST proposals, Treasury proposals and Calibration proposals. Archival proposal include Theory proposals, Community Data Science Software proposals and Calibration (AR) proposals. A full description of the proposal categories is given in the Call for Proposals.

Each proposal is assigned to one of seven science categories:

  1. Solar System Astronomy,
  2. Exoplanets and Exoplanet Formation,
  3. Stellar Physics and Stellar Types,
  4. Stellar Populations (and the ISM),
  5. Galaxies,
  6. Supermassive Black Holes and Active Galaxies,
  7. and Large-Scale Structure of the Universe.

JWST Telescope Allocation Committee (TAC)

JWST proposals are selected through competitive peer review. Panelists are chosen based on their scientific expertise in the areas under review by the topical panels. Each topical panel will be managed by a panel Chair, and there will be a Galactic Meeting Chair and an Extragalactic Meeting Chair overseeing the review process. To assist in the review process, each panel will also be assigned a Panel Support Scientist (PSS) and a Leveler; the role of the PSS is to ensure the process runs smoothly and act as liaison between the panel and STScI, and the role of the Leveler is to ensure the discussion remains focused on the scientific merits of the proposals. Proposals will be graded on an absolute scale against the primary criteria:

  • scientific merit within the field,
  • broader importance for astronomy,
  • the strength of the data analysis plan (where applicable),
  • JWST’s unique capabilities are required to achieve the scientific goals.

The TAC co-Chairs, At-Large TAC members, and panel Chairs will form the Executive Committee. The Executive Committee will review the Large GO, Treasury and AR Legacy proposals. The Executive Committee will also rank the Pure Parallel programs, and will adjudicate any cross-panel scientific issues, as needed. All recommendations for the Cycle 1 science program are advisory to the STScI Director, who is responsible for the final allocation of JWST observing time and funding.

Proposal review process

Table 1 summarizes the timeline for the proposal review process. A brief description of each step is described below.

Table 1. Timeline for the Cycle 1 proposal review process

November 24, 2020Cycle 1 Proposal Deadline
December 18, 2020STScI releases proposals to panelists for review and preliminary grading
January 8, 2021Deadline for panelists to identify conflicts of interest and to recommend proposals that should be moved to another Science Category
January 28, 2021Orientation meeting for Panel Chairs
February 3, 2021Deadline for Galactic panelists to submit preliminary grades for proposals that they are assigned
February 4, 2021Orientation meeting for Galactic Panelists
February 6, 2021STScI sends each Galactic panel the list of proposals to be discussed by that panel; panelists should review all those proposals in preparation for the panel meeting. Panelists should also consider whether they wish to raise a triaged proposal for discussion.
February 10, 2021Deadline for Extragalactic panelists to submit preliminary grades for proposals that they are assigned
February 11, 2021Orientation meeting for Extragalactic Panelists
February 12, 2021Deadline for Executive Committee to submit preliminary grades for Large and Treasury proposals that they are assigned
February 13, 2021STScI sends each Extragalactic panel the list of proposals to be discussed by that panel; panelists should review all those proposals in preparation for the panel meeting. Panelists should also consider whether they wish to raise a triaged proposal for discussion.
February 15, 2021STScI releases the list of proposals that will be discussed in the Executive Committee meeting; Committee members should review all those proposals in preparation for the panel meeting.
February 16 - 19, 2021Galactic panels meet
February 22 - 25, 2021Extragalactic panels meet
March 1 - 4, 2021Executive Committee meets
March 11, 2021Deadline for Panel Chairs to submit final consensus reports
April 7, 2021STScI releases Cycle 1 GO Science Program

Proposals reviewed by the virtual panels are subject to a two-stage review process: 1) preliminary grading and triage; and 2) the review meeting.

Stage 1 (December 14 - February 3 Galactic/10 Extragalactic)

  • STScI assigns each proposal a Primary Reviewer, a Secondary Reviewers, and three to four additional graders. The Primary Reviewer is responsible for leading the proposal discussion and writing the consensus report that will be sent to the PI. The Secondary Reviewer(s) is responsible for supporting the proposal discussion and contributing to the consensus report.
  • The Primary and Secondary reviewer and the additional graders submit numerical scores as preliminary grades for the proposals.
  • All reviewers, but particularly the Primary and Secondary reviewers, are strongly encouraged to use the SPIRIT grading system to enter comments summarizing the strengths and weaknesses for their assigned proposals.


  • STScI compiles a ranked list using the averaged preliminary grades and performs a "triage". The top ~60% of proposals are flagged for further discussion during the review meeting, and the rest are declined.
  • At the panel meeting, each panelist has the option of resurrecting one proposal that has been declined.

Stage 2: Preparation for the Galactic/Extragalactic Topical Panel Meetings

  • Panelists review proposals that have been selected for further discussion at the panel meeting. Each panelist has already submitted grades and comments for some but not all of the selected proposals. Panelists should make sure to review all the proposals and can use the SPIRIT system to enter comments for those proposals prior to the meeting.

Stage 2: Galactic (February 16 - 19, 2021)/Extragalactic (February 22 - 25, 2021) Panel Meetings

  • All proposals that pass triage are discussed and re-scored by the relevant topical panel during the panel meeting. For non-Treasury Small, Medium, and Archive proposals, the ranked list produced by the panels will be used to determine resource awards. 
  • The topical panels provide advice to their Panel Chair on the strengths and weaknesses of the Large and/or Treasury programs in their area of expertise.
  • The Primary Reviewers draft consensus report reflecting the scientific assessment of the panel.

Executive Committee Meeting (March 1-4, 2021)

  • The Executive Committee reviews the larger-scale programs and recommends which should be scheduled.

After the TAC Meeting

  • During the week following the TAC meeting, the Panel Chairs review the panel reports for the proposals assigned to their panel for correctness and consistency.

Finalizing the science program

  • The STScI Director reviews the recommendations made by the TAC and approves the final selection.
  • STScI uses the selected proposals to generate the Long Range Plan


  • The results of the proposal review process are sent to the PIs, including the quintile ranking and the consensus reports from the panels

Roles and responsibilities of the panelists

The roles and responsibilities for review members are summarized as follows.

TAC meeting chair(s)

  • Oversee the proposal review process
  • Moderate the discussion of the Large programs at the Executive Committee meeting
  • Review the consensus reports for the Large Programs

For JWST Cycle 1, there are two TAC Chairs to cover separately the Galactic and Extragalactic panel sessions. Both will participate in the Executive Committee review.

At-large members

  • Moderate panel discussion when the Panel Chair has a conflict

Panel chairs

  • Carefully read all Large Programs, regardless of category, and provide written comments on the strengths and weaknesses of the proposals
  • Read and score all proposals assigned
  • Moderate the discussion of the proposals in their panel
  • Discuss the scientific merits of the Large Programs in the Executive Committee meeting and recommend which Large Programs should be awarded telescope time
  • Write consensus reports for Large Programs for which they are assigned Primary Reviewer.
  • Review the consensus reports for the proposals in their panel

Panel members

  • Read and score assigned proposals and provide written comments on the strengths and weaknesses of the proposals
  • Discuss the scientific merits of the proposals with other panel members at the Galactic or Extragalactic topical panel meetings and re-score the proposals
  • Produce final consensus reports for proposals for which they are assigned Primary Reviewer

Panel support scientists (STScI staff members)

  • Serve as intermediaries between Panel Members and STScI, answering any questions that Panel Members might have
  • Record minutes of the panel discussions
  • Bring critical issues to the attention of the Science Policies Group (SPG) and/or relevant STScI technical staff

Levelers (STScI staff members)

  • Focus proposal discussions on the science presented in the proposal
  • Remind panelists of criteria for recommending disqualifications during team expertise discussions

Software tools

STScI has developed the web-based SPIRIT tool to facilitate preliminary grading of the proposals before the TAC meeting and final grading of the proposals during the TAC meeting. Grading assignments can be viewed in SPIRIT (https://spirit.stsci.edu). A Quick Guide to SPIRIT (Reviewer Tool) can be downloaded here.

Next: Selection Criteria and Scoring System

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