Information Technology Reference
In-Depth Information
The operational databases linked to the portal are constantly updated with informa-
tion from the national electronic official journal, the electronic public procurement
platforms and the contracting entities. All that information will serve as a basis for the
development of a wide range of studies and statistical analyses. It is the main source
to the DW created to provide aggregated information about public works procurement
in Portugal: the Public Works Observatory (OOP).
The OOP Data Warehouse (OOP-DW) aggregates information related to two pro-
curement phases: the negotiation and execution of public contracts, which means that
the information is divided into data related to contract formation - Formation of Con-
tract, and data related to contract execution phases - Execution of Contract. The need
to accurately monitor the overall cost of public contracts in the formation phase and
later during its execution phase, are the two driving factors that influence the top
management to adopt a DW technology. In this context, the OOP-DW was launched
as a research challenge to develop a DW schema to be used by business-users and
citizens concerned in analysing public information related to the management of each
contract phase and provide a clear understanding about information reporting devia-
tions in terms of deadlines and prices in each contract.
Table 2 presents a high level view of the star schema that was created. It includes ele-
ven dimensions and two fact tables to promote transparency and enable more informed
decisions. The OOP-DW stores more than 875.787 registered Procedures corres-
ponding to 993.690 Lots (one procedure can have more than one lot), with more
than 7.657 Contracting entities and more than 112.786 Participating
entities, data related to the period August 2008 to November 2014.
Table 2. Multidimensional structure of the OOP Data Warehouse
Dimens ions
Fac ts
Formation of Contract (FoC)
X
X
X
X
X
X
X
X
X
X
Execution of Contract (EoC)
X
X
X
X
X
X
X
X
X
The FoC fact table contains 2.322.836 rows related to the negotiation phase and
the EoC table contains 1.199.680 related to the execution of contracts. The metric
used to demonstrate the technique presented in this paper relates to the price metric,
expressed as follows:
Price (FoC) = (procedure price - proposal price)
Price (EoC)= (real total price - contract price)
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