Kevin W. Boyack Sandia National Laboratories Sackler Colloquium on Mapping Knowledge Domains May 11, 2003 An indicator-based characterization of PNAS Sandia.

An indicator-based characterization of PNASKevin W. Boyack

Sandia National Laboratories

Sackler Colloquium onMapping Knowledge DomainsMay 11, 2003Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States Department of Energy under Contract DE-AC04-94AL85000.

OutlineData sourcesImpact vs. fundingMap of highest impact workTopics and Import-ExportBibliographic coupling and external references

IndicatorsLots of work by NSF, OECDMany ways of countingOften slanted to economicNot often directly correlating inputs and outputsRarely taking any firm standSome studies relating funding and impactMost recent from Britain or Australia (biomed)Few large scale import-export studies

Data SourcesUsed ISI/SCIE data as base setUsed only articles, letters, notes, reviews (ALNR)Did not include commentaries, editorials, correctionsMedline for MeSH termsNIA grants (dollar amounts, durations, etc.)PNAS full text (not used)PNAS tables of contents (topics)

Data Merges

Percentiles vs. CountsThis study uses percentiles exclusively rather than citation countsPercentiles enables cross-year comparisonsOnly 30-40% of papers have more citations than the meanCalculation of percentilesPapers ranked for each year by citation countRankings converted into percentiles

Counts/Percentiles for 1983 Papers

Funding and ImpactEffect of funding typeEffect of funding amount

MeSH Support TypesSupport, U.S. Gov't, P.H.S.NIHSupport, U.S. Gov't, Non-P.H.S.All other US agencies (NSF, DOE, DOD, etc.)Support, Non-U.S. Gov'tUS non-government (academia, industry )Foreign

Funding Categories

Impact by Funding Category

Impact Stability

NIA 4.1% fraction of PNAS

Impact by Grant Amount

Cumulative Histograms by Range

Impact by Publishing Institution

Impact by Institution and Funding

Map of Highest Impact PapersUsed top quartile of cited docs per yearNumber of citations as of 12/31/2002Citation based mapDirect and bibliographic couplingHenry Smalls combined linkage formulaDirect weight of 5 (rather than Smalls 2)Outer references includedDivided into 70 clustersShift in content over time

Top Quartile are Highly Cited

Ordination

Clustering

Highest Impact Map Time Progression

Core (BioMed) Time Progression

Another View

AIDS Research Time Progression

Cluster Timeline

Diagnostic Terms/Topics by Cluster

Diagnostic Terms/Topics by Cluster

PNAS TopicsBIOLOGICAL SCIENCESAgricultural SciencesApplied Biological SciencesBiochemistryBiophysicsCell BiologyDevelopmental BiologyEcologyEvolutionGeneticsImmunologyMedical SciencesMicrobiologyNeurobiologyPharmacologyPhysiologyPlant BiologyPopulation BiologyPsychologyPHYSICAL SCIENCESApplied MathematicsApplied Physical SciencesAstronomyChemistryComputer SciencesEngineeringGeologyGeophysicsMathematicsPhysicsStatisticsSOCIAL SCIENCESAnthropologyEconomic SciencesPsychologySocial Sciences

Impact by PNAS Topic

Topic Import-Export Matrix

Topic Map

More FunLooking for a better way to show evolution of science over time periodsShould show splitting, joining of clusters, rather than the more continuous evolution that our current techniques showMap short time periods (e.g. 2 years) with overlaps and use overlaps to join maps

Big Change in Clusters with One Year1996-19971997-1998

Another Example (3 Year Change)1997-19982000-2001

Bib Coupling Distribution Changes - Why?

Bib Coupling Distribution Changes - Why?

Distribution of ReferencesTop references3194Laemmli UK (1970), Nature 227, 680.2876Maniatis T (1982), Mol Cloning Laboratory.2659Sanger F (1977), P Natl Acad Sci USA 74, 5463.2364Sambrook J (1989), Mol Cloning Laboratory.1149Chirgwin JM (1979), Biochemistry-US 18, 5294.1121Lowry OH (1951), J Biol Chem 193, 265.1051Bradford MM (1976), Anal Biochem 72, 248.1050Maxam AM (1980), Method Enzymol 65, 499.968Southern EM (1975), J Mol Biol 98, 503.951Towbin H (1979), P Natl Acad Sci USA 76, 4350.900Chomczynski P (1987), Anal Biochem 162, 156.787Feinberg AP (1983), Anal Biochem 132, 6.588Rigby PWJ (1977), J Mol Biol 113, 237.579Thomas PS (1980), P Nat Acad Sci US-B 77, 5201.575Miller JH (1972), Expt Mol Genetics.

Distribution of ReferencesTop references3194Laemmli UK (1970), Nature 227, 680.2876Maniatis T (1982), Mol Cloning Laboratory.2659Sanger F (1977), P Natl Acad Sci USA 74, 5463.2364Sambrook J (1989), Mol Cloning Laboratory.1149Chirgwin JM (1979), Biochemistry-US 18, 5294.1121Lowry OH (1951), J Biol Chem 193, 265.1051Bradford MM (1976), Anal Biochem 72, 248.1050Maxam AM (1980), Method Enzymol 65, 499.968Southern EM (1975), J Mol Biol 98, 503.951Towbin H (1979), P Natl Acad Sci USA 76, 4350.900Chomczynski P (1987), Anal Biochem 162, 156.787Feinberg AP (1983), Anal Biochem 132, 6.588Rigby PWJ (1977), J Mol Biol 113, 237.579Thomas PS (1980), P Nat Acad Sci US-B 77, 5201.575Miller JH (1972), Expt Mol Genetics.

Distribution of References

Few References Account for TailAll references31 references removed

Questions and Things to DoHow to best show the real evolution of science?Does this indicate a lack of a new biomedical revolution to drive the next generation research?Compare coupling distributions of PNAS to other journals