A first step to the evaluation of healthcare quality
BACKGROUND AND JUSTIFICATION
Quality is a concept widely used in our days when we want to evaluate a certain aspect. However, it is considerably difficult to find a universal definition that can be used and understood by everyone due to its subjectivity. As in all areas of interest, the quality in health is also a multidimensional concept and it includes not only the notion of clinical quality but also social, economical, ethical and physical aspects.  Taking this into account, it is easy to understand that the global quality of a health system is the average of the values assigned to each of the dimensions mentioned above.
In spite of the subjectivity of the concept “quality”, it is important to establish terms of comparison in order to analyze the performance of health systems and its evolution, and thus improve the conditions of health services. Besides, we must not forget the constant search for healthcare by a more and more aged population, and also by more informed and demanding people. After all, patient satisfaction is important as it may reflect the quality of the health care. However, “patient satisfaction or dissatisfaction is a complicated phenomenon that is linked to patients' expectations, health status, and personal characteristics, as well as health system characteristics”. 
Therefore, governments are increasingly introducing performance management systems to improve the quality and outcomes of healthcare.  Even though it is not an easy task, as it is impossible to find the perfect evaluation system, it must be accomplished with responsibility in order to develop the best methods. “Given the importance of healthcare, it seems inconceivable that we do not have excellent ways of evaluating how well we are doing”. 
To do so, many surveys were made to discover which quality aspects of a hospital performance must be analyzed, not only to improve the quality of hospital care but also to find out patients and doctors’ opinion about the relevance of the quality indicators that are included in hospital reports. 
One of the used case mix classification systems are Diagnosis Related Groups (DRGs) and, more specifically, indicators. 
DRGs are “a system for classifying patient care by relating common characteristics such as diagnosis, treatment, and age to an expected consumption of hospital resources and length of stay. Its purpose is to provide a framework for specifying case mix and to reduce hospital costs and reimbursements and it forms the cornerstone of the prospective payment system”. 
Every Portuguese hospital keeps a permanent database about their patients to classify them in DRGs, and that information is sent periodically to Administração Central do Sistema de Saúde (ACSS). It’s at ACSS that data is processed for cost calculation in order to make more accurate budgets. 
Indicators can be defined as measurement units that allow monitoring and evaluation of key variables of an organization through comparison with its corresponding internal and external referential.  So, indicators are empirical instruments that allow us to show the theorical dimension of a key variable. Specifically, healthcare indicators are measurements that reflect relevant information about different attributes, health dimensions and factors that influence health system performance. [11-12] With the information given by these instruments, governments can know how much money was spent and where it was used (normally prices per DRGs), as well as understand where it is needed. [13-14]
Then, there are some indicators that can provide us useful information about the performance of a hospital, such as mortality, length of stay, postponed surgeries, outpatient department episodes, outpatient surgery, childbirth of cesarean operation, principal diagnosis, and finally surgical proceedings (and complications).  All of these will be used as sources of data in our study.
We can see, by the examples of foreign countries, that the information given by these indicators is very useful, as well as the performance measurements. For instance, Australia has introduced a National Quality and Performance System (NQPS) with the purpose of establishing a higher performance, promote best practice, support under performance and sharpen the focus of healthcare institutions.  To accomplish those goals, about 52 indicators (National Performance Indicators-NPI) are analyzed. These indicators are concerned with governance, prevention and early intervention access, integration and chronic diseases management.
In the USA, a study was done to evaluate if the 7 surgeries chosen as quality indicators by the Agency for Healthcare Research and Quality were performed frequently enough to identify hospitals with increased mortality rates.  To do that, a large number of data from different hospitals and from different gaps of time was used to turn possible the representation of all hospitals in the country. Analysing the results of this study, we easily understand that for only one surgery, the majority of hospitals exceed the minimum caseload and for the remainder just a small number of hospitals met the minimum caseload required.
So, using this indicator, we are assuming that one hospital with great results in this 7 surgeries is an excellent hospital but that might not be exactly true, because this hospital could have this results simply because his activity is very low in this kind of operations. This way, patients are falsely reassured that they are choosing a safe hospital basing their choice in this indicator.
The main conclusion of this study was that the policy makers should consider sample size in selecting the best quality measure for specific procedures, particularly when data is used for public reporting. [17-18] Otherwise, they run the risk of mislabelling hospitals and misinforming patients.
With the importance given by the Australian and American authorities, we can confirm the importance of having regular analyses to improve management policies.  We can also use these examples to avoid measurement errors.
In this study, we had access to specific information about a central hospital through a number of healthcare quality indicators. The aim of this project is to analyze these indicators (the ones referred above) and obtain information that may be useful in the future to study the evolution of the hospital healthcare.
RESEARCH QUESTION AND AIMS
The main question in this study is related to how the indicators evolved through the years in the chosen central hospital. According to this, our general purpose was the calculation of the indicators’ values concerning the proposed variables. Some specific aims can be also be referred, such as the examination of the quality of healthcare by analysing the evolution of mortality, postponed surgeries, surgical procedures, among others; the definition of an hospital’s activity and production by using the data related with indicators as, for instance, length of stay, outpatient episodes, outpatient surgery and childbirth of caesarean operation; and finally the use of main diagnosis to study the quality of the available data.