Proposals to the National Radio Astronomy Observatory (NRAO) and the Green Bank Observatory (GBO) are evaluated on a competitive basis using a joint panel review system run by the NRAO.  This includes the following facilities: the Karl G. Jansky Very Large Array (VLA), the Robert C. Byrd Green Bank Telescope (GBT), and the Very Long Baseline Array (VLBA)/High Sensitivity Array (HSA). Three proposal types can be submitted for the standard deadlines of 1 Feb and 1 Aug each year: Regular, Large, and Triggered.  Director's Discretionary Time (DDT) may be submitted at any time and are reviewed by the observatory scientific staff on the basis of the proposals' scientific merit and technical feasibility.  DDT proposals are for Target of Opportunity proposals or Exploratory Time.  Here we discuss the review process for proposals submitted during one of the deadlines.  Also see the presentation by Joan Wrobel.

Technical Review

All proposals are reviewed for their technical feasibility by the observatory staff.   These are made available for the SRP Consensus Review (see below).

Scientific Review

Proposals are evaluated for their scientific merit by science review panels (SRPs) which correspond to different areas of scientific research. Each SRP consists of at least 5 reviewers plus a chair.  Each proposal goes through an individual and consensus review.

1. Individual Review. After all SRP members declare their conflicts the SRP chair will assign reviewers to all proposals.  Each proposal will be allocated one primary reviewer, one secondary reviewer, and two or more tertiary reviewers, all of which will provide an individual review consisting of a score from 0.1 to 9.9 (lower scores are better) and a comment. The goal is to have at least 4 reviewers per proposal (or 5 reviewers for Large proposals).  Once all of the individual reviews are completed the scores are normalized for each SRP with an average value of 5 and a standard deviation of 2.
2. Consensus Review. Each SRP will meet remotely to produce a consensus review that consists of an SRP score and a comment.  The SRP score is typically the normalized score but can be adjusted by consensus. After the consensus reviews are completed the proposals in a given SRP are rank-ordered and normalized between 0-10.  Specifically, R*10/N where R is the rank (1, 2, 3, etc.) and N is the number of proposals in the SRP. These linear rank-ordered scores for all the SRPs are then merged.

TAC Review

The Telescope Time Allocation Committee (TAC) consists of the SRP chairs with one serving as the TAC chair.  The purpose of the TAC is not to re-visit the scientific merit of a given proposal. They will, however, weigh the relative merits of different proposals in light of technical, scheduling, and programmatic constraints. The primary task of the TAC is to consider the merged list of linear rank-ordered proposals and to make recommendations regarding time allocation and scheduling priority for each proposal.  There are five different scheduling priorities:

• Priority A.  This is the highest scheduling priority; the observations will almost certainly be scheduled. For the GBT and the VLBA, the observations will be considered for scheduling for up to two semesters. For the VLA, the observations will be considered for scheduling for two VLA configuration cycles.
• Priority B.  This is the next highest scheduling priority; the observations will be scheduled on a best effort basis. For the GBT and VLBA, the observations will only be considered for scheduling for one semester. For the VLA, the observations becomes ineligible when the associated configuration ends.
• Priority C.  A lower scheduling priority; the observations are not guaranteed to be scheduled and are used to supplement gaps (e.g., filler time) in LST/GST ranges not filled by higher priority proposals. For the GBT and VLBA, the observations will only be considered for scheduling for one semester. For the VLA, the observations becomes ineligible when the associated configuration ends.
• Priority D.  The lowest scheduling priority; the observations have a low probability of being scheduled and are used as secondary filler when higher scheduler priorities cannot be scheduled. For the GBT and VLBA, the observations will only be considered for scheduling for one semester. For the VLA, the observations becomes ineligible when the associated configuration ends.
• Priority N. The observations will not be scheduled.

Directors' Review

The Directors' Review is a meeting held each semester involving the observatory Directors, Chief Scientists, the NRAO Assistant Director for Science Support and Research, and observatory staff relevant to the time allocation process and telescope scheduling. The proposal evaluation and time allocation process is reviewed to ensure that all relevant NRAO policies and procedures have been followed, resulting in fair and transparent allocation of telescope time. The observatory Director may make adjustments to the scheduling priority and time recommended by the TAC in response to programmatic concerns.  The approved rank-ordered lists are then sent to the sites for scheduling and the users are notified of the final disposition of their proposals.