VLDB'2001 Program Committee Chairs and General Chair
The Specificity Factor (Spf)
(Stefano Ceri, Peter Apers, Kotagiri Ramamohanarao, Richard Snodgrass,
and Paolo Atzeni)
Many have noted that the papers appearing in recent database conferences
such as VLDB and SIGMOD are getting more and more specific. Ten years ago,
there were papers introducing new data models, query languages, and
conceptual notations; one encounters few such papers today. This is in some
way inevitable, as the field matures and as a literature and set of
accepted concepts and paradigms becomes prevalent. Therein also lies the
danger that the field is becoming ossified, that papers counter to the
prevailing wisdom are rejected in favor of thorough studies of narrow topics
of interest to only a few people.
Asilomar report labels these latter papers "delta-X" papers, and
recommends a radical approach of going to poster sessions and invited papers
for conferences. We do not agree with such a disruptive strategy, preferring
instead a more evolutionary approach that encourages broader papers.
The Spf is a rating that is a single digit, with a larger Spf indicating
the paper is more specific, and thus appeals to a smaller portion of the
community. While more specific papers should not be rejected out of hand,
they need to be particularly compelling to be selected over less specific
The Spf is designed to be determined quickly, from a paper's title and
abstract. Studies will be needed to determine whether the Spf is a
well-defined metric; for this reason, we will not include it in the overall
ranking computed for each paper, but will instead just have it available
as one of the many considerations kept in mind when the paper is evaluated,
both by the individual program committee members and during the final
discussion at the program committee meeting.
Very generally, 1 (one) is added to the Spf for each significant reduction
in the paper's domain of applicability. To provide an absolute scale, we
list some rough guidelines. The guidelines are incomplete, and are intended
only to be illustrative. Each successive level assumes everything in the
previous levels fixed and known.
||The paper introduces a new benefit to humanity (after all, that
is ultimately why we are in this business).
||The paper introduces a new means to effect a known benefit to
||The paper introduces a new class of software to implement a known
means to help humanity. This software manages data in some way, but
the paper itself is not particular to a data model or query language.
||The paper introduces a new or altered data model to support an
existing class of software.
||The paper introduces a new or improved query language or design
notation or conceptual modeling technique for an existing data model.
||The paper introduces a new or improved query optimization or evaluation
technique to support an existing query language, or a new construct
for an existing conceptual modeling technique.
||The paper introduces a new or improved input to an existing query
optimization or evaluation technique, or a new or improved way to
determine the configuration of an existing conceptual modeling
||The paper introduces a new or improved way to calculate or estimate
or tune an existing input to an existing query optimization technique.
One determines the Spf by first identifying where the paper falls vis-a-vis
this range from 0 to 7, then adding one unit for each significant
restriction on applicability (such as a paper applying to only one or a few
operators of a query language) or not including a major part of the space
(such as working only on select-project-join queries).
As examples, here are nonsensical (we hope!) titles at some of the Spf levels.
The "Hysterical" Data Model to Support Time-varying but Space-constant Data
The Hyperbolical Query Language to Support the Hysterical Data Model
New Space-constant Optimizations for the Hyperbolical Query Language
Circular Histograms for Use in Space-constant Optimizers
Fast Reconstruction of Circular Histograms
New Space-constant Optimizations for Aggregates in the Hyperbolical
New Space-constant Optimizations for Correlated Subqueries in the
Hyperbolical Query Language on Shared-Nothing Multiprocessors
Tuning Circular Histograms for Use with Non-Materialized Views in a
This last paper has the following significant restrictions in its domain of
- Applies only to applications managing time-varying but space-constant data
- Assumes the hysterical data model used for such applications; unclear
whether it would apply to other data models
- Assumes the hyperbolical query language for that data model
- Assumes space-constant optimizers for this language; unclear whether it
would apply to other optimizer approaches for this language
- Assumes circular histograms for such optimizers
- Considers only the tuning of such histograms
- Considers reconstruction only for use with non-materialized views
- Applies only in a low-memory environment; unclear whether it would apply
when memory was prevalent
Given that this paper has a quite high Spf, it had better be pretty exciting
to be preferred over, say a paper introducing new optimizations for the
hyperbolical query language. The reason that Spf is only a single digit is
that it is difficult to imagine a paper with a multi-digit Spf that anyone
would want to read, though we're sure we'll be proven wrong some day.
Note also that the number of possible papers goes up exponentially with Spf.
There are probably only a few dozen papers legitimately at Spf 2, and
perhaps a few hundred papers at Spf 3. But at Spf 7, the number of possible
papers, most of which are uninteresting, is mind-boggling.
Our informal experience with papers submitted to previous VLDB's (and
SIGMOD's) is that most papers have an Spf between 4 and 7, with the
particular ones at 7 quite narrow. Also, the title often doesn't reveal
major restrictions to the applicability, but the abstract generally does
(and should). Sometimes, the Spf increased by a unit when reading the paper,
as a major restriction became apparent that wasn't mentioned in the title or
abstract, indicating that the abstract and perhaps the title should be
changed to make the restriction more explicit.
Our experience also is that many papers with a high Spf are excellent
papers according to the accepted criteria. Their proposed approach is often
fully described, the empirical studies quite thorough, with a large range of
parameters that are varied. This makes sense, as it is easier to be thorough
in a narrow domain than in one that is broader and more varied. This is one
of the reasons that prototypical papers in VLDB and other high quality
conferences have over time evolved into detailed studies of highly specific
and well-defined questions, of interest to only a few people.