Overview

The ALMA proposal review process is organized by the Proposal Handling Team (PHT) at the Joint ALMA Observatory (JAO). ALMA proposals are selected by competitive peer review through either the distributed peer review process or the ALMA Proposal Review Committee (APRC).

Proposals that request less than 50 h on the 12-m Array or less than 150 h on the 7-m Array in standalone mode are reviewed using the distributed peer review system, in which the proposal team designates one member to participate in the review process. The outcomes of the distributed peer review process are:

• A scientifically ranked list of proposals
• Individual comments for each proposal written by the reviewers that are sent to the Principal Investigators (PIs).

Large Programs, i.e., proposals that request more than 50 h on the 12-m Array or more than 150 h on the 7-m Array in standalone mode, are reviewed by the APRC, a panel composed of experts selected from the international astronomical community. To ensure a thorough evaluation, external Science Assessors also provide reviews for Large Programs, which are considered by the APRC. The outcomes of the APRC review process are:

• A list of recommended Large Programs
• A consensus report for each Large Program that summarizes the strengths and weaknesses of the proposal.

All proposals are reviewed in a dual anonymous fashion in which the proposers do not know the identity of the reviewers and the reviewers do not know the identity of the proposers. All proposals need to be prepared in accordance with the dual-anonymous guidelines.

Distributed peer review plenary session

The PHT will host a series of Webinars to explain the distributed peer review process and answer questions. Slides and a recording of the presentation will be available on this web page. Reviewers and mentors are strongly encouraged to attend one of the sessions or watch the recording at their convenience. The Webinars will take place between 8-13 May 2025, with times scheduled to accommodate participants across all ALMA regions. Reviewers and mentors are welcome to join the session that best suits their schedule. The schedule for the three sessions is as follows:

Session 1: Thursday May 8, 2025, 17:00 UTC

Session 2: Friday May 9, 2025, 13:00 UTC

Session 3: Tuesday May 13, 2025, 2:00 UTC 

Prior to the Webinars, the PHT will send an email to all reviewers and mentors with more detailed information.

Available documents for the proposal review process

 

Document	Description
Dual-anonymous Guidelines	Provides guidelines for PIs on how to write their proposals in a dual-anonymous fashion
Overview of Distributed Peer Review	Detailed description of the distributed peer review process
Guidelines for Reviewers	Guidelines for reviewing proposals and writing comments to the PIs
Reviewer Tool and User’s Manual	Reviewer Tool and user’s manual
Frequently asked questions	Contains answers to questions about the dual-anonymous format and distributed peer review

 

New in Cycle 12

• A reviewer can be assigned a maximum of THREE Proposal Sets; i.e., 30 proposals. More information is provided on the web page Overview of Distributed Peer Review.
• Feedback on Review Comments: To help improve the review process, we invite reviewers to rate the effectiveness of a random selection of reviews within your proposal set. The Guidelines for Reviewers contains more information.
• ALMA has adopted a policy on the use of Generative Artificial Intelligence (GAI) tools, such as large language models (e.g., ChatGPT), by proposal authors and reviewers. The Guidelines for Reviewers contains further information.

Proposal review timeline

Table 1 summarizes the timeline of the Cycle 12 Distributed Peer Review process, and Table 2 summarizes the timeline of the Large Programs Cycle 12 review process. A brief description of each step is given below. 

Table 1: Timeline for the Distributed Peer Review Process

Date	Milestone
29 April 2025	Deadline for reviewers to provide their scientific expertise and their list of conflicts of interest before proposals are assigned.
07 May 2025	Proposals are released. Stage 1 begins for the distributed peer review.
14 May 2025	Deadline to provide conflicts of interest.
04 June 2025	Distributed peer review Stage 1 deadline.
05 June 2025	Distributed peer review Stage 2 begins.
19 June 2025	Distributed peer review Stage 2 deadline.
August 2025	Results sent to PIs.

 

Table 2: Timeline for the Large Programs Proposal Review

Date	Milestone
02 May 2025	Distribution of review material to the Science Assessors and start of Stage 1.
09 May 2025	Deadline for the Science Assessors to provide conflicts of interest.
30 May 2025	Stage 1 Large Programs review deadline.
03 – 15 June 2025	APRC members draft consensus reports in preparation for the APRC meeting.
16 – 20 June 2025	APRC meeting.
23 – 27 June 2025	APRC members finalize the consensus reports.

 

Distributed peer review

The distributed review process proceeds in two stages as described below. A complete description of the process can be found here.

Stage 1

The PHT will assign 10 proposals (a “Proposal Set”) to the reviewer on behalf of each proposal in which they are the designated reviewer.

The reviewers will rank the proposals within a Proposal Set from 1 (strongest) to 10 (weakest) and write a review for each proposal that indicates its strengths and weaknesses.

Stage 1 is mandatory. Reviewers must submit their reviews by the Stage 1 deadline (04 June 2025, 15:00 UTC) or the corresponding proposal for which they were identified as the designated reviewer may be disqualified.

Stage 2

Reviewers read the anonymized comments from the other reviewers and revise their own ranks and reviews as needed.

The deadline to complete Stage 2 is 19 June 2025, 15:00 UTC. If a reviewer does not submit the Stage 2 ranks and reviews, then the Stage 1 ranks and reviews will be considered final.

ALMA Proposal Review Committee

Large Programs are reviewed by the APRC. The general steps for the assessment of these proposals are outlined below.

Stage 1

The APRC members review their assigned proposals, provide a numerical score for the proposals, and write comments summarizing the strengths and weaknesses of the proposal. The PHT assigns each Large Program a Primary Assessor, who is responsible for leading the proposal discussing in Stage 2 and writing the consensus report that will be sent to the PI.

External Science Assessors review a small number (1-3) of Large Programs in their area of expertise and provide a written report with their reviews, which are provided to the APRC.

Stage 2

The APRC reads the reports of the external Science Assessors in preparation for the meeting. The APRC discusses the proposals and recommends which Large Programs should be scheduled. The Primary Assessors write consensus reports to reflect the final scientific assessment.

Queue building

The primary outcome of the proposal review process is a scientifically ranked list of proposals. The list is generated using two main inputs: 1) the proposal rankings of Proposal Sets from individual reviewers in distributed peer review, and 2) the ranked list of Large Programs recommended by the APRC.

In distributed peer review, each reviewer ranks their assigned proposals from 1 (strongest) to 10 (weakest). The rankings from individual reviewers are combined to form an overall ranked list. For a given proposal, the highest and lowest ranks are dropped to remove possible outliers. The remaining ranks are averaged and normalized by scientific category.  The sorted list of average ranks determines the overall scientific ranked list of proposals.

The ranked list of proposals establishes the priority order to build the observing queue.  The Large Programs recommended by the APRC have first priority in building the queue, but they are limited to how much time they can fill in a configuration/LST, as described in the Proposer’s Guide. Creating the observing queue also takes into consideration the available time in specific configurations and LST ranges, time allocated to each ALMA Executive, and historical weather conditions for a given receiver band and frequency. It is during the queue-building stage that the priority grades (A, B, C) are assigned, or declined depending on the amount of telescope time available. Because numerous factors are considered in building the queue, it is possible for a high ranked proposal to be declined while a lower ranked proposal is accepted.

After the ranked list is generated and the observing queue is created, the ranked list and the priority grades are submitted to the ALMA Director for approval. After the Director’s approval, the results are sent to representatives from East Asia, Europe, North America, and Chile for final approval. Principal Investigators are then notified of the results.