Tracking Chandra Science Productivity

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Tracking Chandra Science Productivity

• Publication Metrics

Paul J. Green (CDO)
special thanks to Mihoko Yukita (CDO) Sherry
Winkelman (Archive Group)
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Why Use Publications?

• An accepted measure of scientific productivity.
• Existing databases (e.g., ADS) allow trackable,
  reproducible statistics.
• Comparisons can be made to other observatories.
• What else is there? (News articles, Press
  releases, funding)

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Which Metrics?

• PhD dissertations
• papers
• citations
• pages
• including
• all publications
• refereed papers
• highly cited papers
• certain journals

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Chandra Bibliography Database
See Archive Group presentation A. Rots

• Queries the ADS daily.
• Requires human scanning, culling, and
  categorization.
• Allows searching and statistics.
• Database now current and backfilled to launch.
• Plans for public search page soon, with links to
  related data.

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TOTALS BY YEAR

• Refereed only
• All proposal types GO, GTO, TOO, DDT
• (no CAL)
• Statistics through 18 Dec 2003
• Colored by paper category

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S(Chandra Papers published that year)
Illustrates ramp-up in operations, archive size,
user familiarity
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S(Citations in that year to all previous Chandra
Papers)
Same ramp-ups convolved with publication-to-citati
on delay.
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MEANS BY YEAR

• Refereed, Category 1 only
• All proposal types GO, GTO, TOO, DDT
• (no CAL)
• Statistics through 18 Dec 2003
• Colored by paper category
• N.B. multiple countings

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S(Papers published in each year)/ S(Targets used
in those Papers)
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Comparisons

• Comparing to other scopes is tricky, e.g.,
• Whos the audience?
• Whats the purpose?
• How do you normalize paper or citation counts ?
• aperture area? (meaningless across
  wavelengths)
• program dollars? (space vs. ground!)
• photons?
• pointings!
• HST has 15x the citation impact of a 4-m
• ground-based telescope, but costs 100x as much.
• Benn Sanchez 2001, PASP, 113

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Doctoral Theses

• Searching the dissertation abstracts
• http//lib.harvard.edu/e-resources/details/d/dissa
  bst.html
• as of 22 Dec 2003
• Year Chandra AND HST OR
• X-ray Hubble Space Telescope
• 1999 1 7
• 2000 5 10
• 2001 9 5
• 2002 9 6
• 2003 7 4
• TOTAL 31 32

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Other Trends for Study

• The CXC Archive group database also allows study
  of publication metrics by
• journal (e.g., Nature citation rate 8x ApJ)
• most-cited papers
• observation type (DDT, TOO, LP, VLP)
• subject area
• PI institution
• proposal grade
• These all take effort!

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Upcoming Public Metrics Page

• Simple statistics, updated monthly
• Omit inter-telescope comparisons
• Links to Chandra Bibliography Database