EViews – Ein Ökonometrisches Werkzeug

Programmierung ist für viele Anwender nicht angenehm! Im Gegensatz zu manch anderer Ökonometriesoftware muß man bei EViews keine komplizierten Kommandos beherrschen. Fast alle Möglichkeiten von EViews können mit nur einen Mausklick aufgerufen werden.

Es sind dies die in der praktischen Ökonometrie am häufigsten verwendeten Verfahren:

Grundlegende statistische Verfahren

Einfache deskriptive statistische Kennzahlen (Mittelwert, Standardabweichung,...) können sowohl für die gesamte Stichprobe als auch aufgeteilt nach den Kategorien einer oder mehrerer Variablen berechnet werden. Sie können ebenfalls Querschnittsanalysen oder Perioden in den "gepoolten" Daten auswählen. Die standard Hypothesentests für Mittelwerte, Mediane und Varianzen können genauso leicht ausgeführt werden wie der Test auf Gleichheit zweier Zeitreihen bzw. Gleichheit innerhalb einer Zeitreihe, die nach einer anderen Variable klassifiziert wird ( dies ermöglicht auch die einweg Varianzanalyse).
Folgende graphische Darstellungen sind möglich: Histogramme, kumulierte Verteilungen, Überlebensfunktion (survivor) und Quantilplots. Die QQ-Plots erlauben den paarweisen Vergleich der Verteilungen zweier Zeitreihen oder den Vergleich der Verteilung einer Zeitreihe mit einer theoretischen, angenommenen Verteilung, dabei sind viele verschiedene Verteilungsformen möglich. Ebenfalls können verschiedene Verteilungsanpassungstests (Normal-, Exponential-, Extremwert-, Logistische, Chi-quadrat-, Weibull- oder Gammaverteilung) durchgeführt werden, dazu gehören Kolmogorov-Smirnov, Liliefors, Cramer von Mises und Anderson-Darling. Die Parameter der Verteilung können entweder von Ihnen vorgegeben werden oder EViews schätzt die Parameter aus Ihren Daten. EViews berechnet auch Kerndichteschätzer und erzeugt Scatterplots (Punktwolken) einschließlich Kurvenanpassung ( einfache Regression, transformierte Regression, "kernel" und "nearst neighbor" Regression).
Folgende weitere Verfahren werden angeboten: Einheitswurzel-Test (ADF und Phillips-Perron), Test auf Cointegration, Test auf Kausalität (Granger), Autokorrelation, partielle Autokorrelationsfunktion, Q-Statistik und Kreuzkorrelationsfunktion.
EViews hat auch Zufallszahlengeneratoren für insgesamt 18 verschiedene Verteilungen. Das erzeugen neuer Zeitreihen und Matrizen ist deren häufigste Anwendung.

Saisonkomponenten

EViews beherrscht sowohl additive als auch multiplikative Saisonkomponentenzerlegung und unterstützt die X11 sowie das neue X12 Verfahren des "U.S. Census Bureau" und das Tramo/Seats Verfahren. Das Tramo (Time Series Regression with ARIMA Noise, Missing Observations, and Outliers) Verfahren ermöglicht die Schätzung, Vorhersage und Interpolation von Zeitreihen auch wenn die Daten nicht vollständig sind und ARIMA Fehler zeigen, auch möglicherweise vorhandene Ausreisser (verschiedener Ausreissertypen) werden dabei korrekt berücksichtigt. Die Seats (Signal Extraction in ARIMA Time Series) Methode zerlegt die Zeitreihe, auf der Basis des ARIMA Modells, in nicht beobachteten Komponenten.

Schätzung

EViews bietet eine Vielzahl verschiedener Methoden für die Schätzung von Modellen ( einfache und auch multiple) für Zeitreihen- und Querschnittsdaten. Die Grundlage bilden dabei Verfahren wie "einfache kleinste Quadrate" (multiple Regression), "zwei Schritt kleinste Quadrate" und "nichtlineare kleiste Quadrate". Gewichtete Schätzungen sind für alle Verfahren möglich. Sie können auch "polynoimale Lag Strukturen" für beleibig viele unabhängige Variable spezifizieren.
Zusätzlich zu den oben beschriebenen grundlegenden Schätzverfahren bietet EViews auch Schätzung und diagnostische Kennzahlen für verschiedene weiterentwickelte Modelle.
EViews hochentwichelte Rechenverfahren bieten analytische Ableitungen der meisten nicht linearen Regressionsmodelle.

ARCH models

You may estimate a variety of Autoregressive Conditional Heteroskedasticity (ARCH) models. EViews handles GARCH(p,q), EGARCH, TARCH, and Component GARCH specifications. The mean equation of ARCH models may include ARCH and ARMA terms, and both the mean and variance equations allow for exogenous variables.

Generalized Method of Moments

EViews supports GMM estimation for both cross-section and time series data (single and multiple equation). Weighting options include the White covariance matrix for cross-section data and a variety of HAC covariance matrices for time series data. The HAC options include prewhitening, either quadratic or Bartlett kernels, and fixed, Andrews, or Newey-West bandwith selection methods.

Limited Dependent Variables

EViews estimates models for binary, ordered, censored and truncated (Tobit), and count data. The binary, ordered, censored, and truncated models may be estimated for likelihood functions based on normal, logistic, and extreme value errors. Count models may use Poisson, negative binomial, and quasi-maximum likelihood (QML) specifications. EViews optionally reports generalized linear model or QML standard errors.

System Estimation

EViews supports estimation of both linear and nonlinear systems of equations by OLS, two-stage least squares, seemingly unrelated regression, three-stage least squares, GMM, and FIML. The system may contain cross equation restrictions and autoregressive errors of any order.

Vector Autoregression

Vector Autoregression and Vector Error Correction models are easily estimated. Once estimated, you may examine the impulse response functions and variance decompositions for the VAR or VEC. VAR impulse response functions and decompositions feature standard errors calculated either analytically or by monte carlo methods (analytic not available for decompositions) and may be displayed in a variety of graphical and tabular formats.
You may impose and test linear restrictions on the cointegrating relations and/or adjustment coefficients. EViews VARs also along you to estimate Structural factorizations (VARs) by imposing short-run (Sims 1986) or long-run (Blanchard and Quah 1989) restrictions.Over-identifying restrictions may be tested using the LR statistic reported by EViews.
VAR views allow you to examine the structure of your specification. With a few clicks of the mouse, you can display the inverse roots of the characteristic AR polynomial, perform Granger causality and joint lag exclusion tests, evaluate various lag length criteria, view correlograms and autocorrelations, or perform various multivariate residual bsaed diagnostics.

Pooled Time Series-Cross Section

EViews features a Pool object designed to facilitate working with pooled, time series-cross section data. Unbalanced or balanced data sets with unlimited length time series and up to several hundred cross sections are easily analyzed.
Estimation options include fixed and random effect specifications for the intercept, weighted least squares, and seemingly unrelated regression, plus all of the estimators allowed for EViews system objects. Coefficients on specific variables (including AR terms) can be constrained to be identical, or allowed to differ across the cross-section.

State-Space Models

A sspace object allows estimation of a wide variety of single- and multi-equation models dynamic structural time-series models using the Kalman Filter algorithm. Among other things, you can use the sspace object to estimate random and time-varying coefficient models and ML ARMA specifications.
Sophisticated procs and views give you access to powerful filtering and smoothing tools so that you can view or generate one-step ahead, filtered, smoothed signals, states, errors, etc. EViews' built-in forecasting procedures also provide easy-to-use tools for in- and out-of-sample forecasting using n-step ahead or smoothed values.

User-Defined Maximum Likelihood Estimation

EViews features an object (the LogL) for handling user-specified maximum likelihood estimation problems. Simply use standard EViews expressions to describe the log likelihood contribution of each observation in your sample, and EViews will do the rest...

Specification Evaluation and Diagnostics

Once an equation or system is estimated, you can use EViews to perform a wide array of specification evaluation and diagnostic tests.
These tests include Wald tests of linear and nonlinear coefficient restrictions, likelihood ratio and F-tests for omitted variables, Lagrange multiplier tests for serial correlation and ARCH, White heteroskedasticity tests, Ramsey RESET tests, and Chow forecast and breakpoint tests.
Additional tests exist for specific models. As with other object views, all hypothesis tests can be generated by a simple menu selection from an equation or system window.

Forecasting and Simulation

With EViews, you need not concern yourself about the complexities of making forecasts. You can concentrate on the substance of the forecasting problem. For single equation models, just select a menu item and EViews will compute a static or dynamic forecast with optional forecast standard errors and a graph of the 95 percent forecast confidence. Successful forecasting equations can be saved in your workfile or stored in an EViews database.

Simultaneous Equation Solution and Simulation

The model object, which is used for simultaneous equation simulation and solution provides the features most commonly requested by model builders.
Variable dependencies and the block structure of the model's equations are displayed with a simple mouse click. Reference equations by name and the model is updated automatically whenever the equation is reestimated. You can even use the model to manage multiple solution scenarios for comparing simulation results under various sets of assumptions.
The EViews model object makes it easy to perform non-stochastic or stochastic simulation using either Gauss-Seidel or Newton solvers. Built-in views and procedures display simulation results in graphical or tabular form. Forward solution (currently unavailable with stochastic solution) allows you to solve for model consistent expectations. EViews provides sophisticated add factor support, including equation normalization. You can even solve simple control problems where the values for an exogenous control variable are found so that an endogenous variable achieves a user specified target.

Data Management

Powerful modeling tools are only useful if you can easily access your data. EViews provides the widest range of data management tools available in any econometric software.

Extensive Function Library

EViews contains an extensive library of functions for working with and transforming your data. In addition to standard mathematical and trigonometric functions, EViews provides functions for computing descriptive statistics, specialized date and time series data functions, functions for working with a variety of statistical distributions, as well as special functions.

Sophisticated Expression Handling

EViews powerful tools for expression handling mean that you can use expressions virtually anyplace you would use a series. You don't have to create new variables to work with the logarithm of Y, the moving average of W, or the ratio of X to Y (or any other valid expression). Instead, you can use the expression in compute descriptive statistics, as part of an equation or model specification, or in constructing graphs.
When you forecast using an equation with an expression for the dependent variable, EViews will (if possible) allow you to forecast the underlying dependent variable and will adjust the estimated confidence interval accordingly. For example, if the dependent variable is specified as LOG(Y), you can elect to forecast either the log or the level of Y, and to compute the appropriate, possibly asymmetric, confidence interval.

EViews Databases

EViews has built-in database features. An EViews database is a collection of EViews objects maintained in a single file on disk. It need not be loaded into memory in order to access an object inside it, and the objects in the database are not restricted to being of a single frequency or range. EViews databases support powerful query features which can be used to search through the database for a particular series or select a set of series with a common property.

Series contained in EViews databases may be accessed and used by EViews procedures without being fetched into workfiles. Automatic search capabilities allow you to specify a list of databases to be searched when a series you need cannot be found in the current workfile.

Database Support for RATS, TSP, GiveWin, and Aremos TSD Files

EViews supports RATS, TSP, PcGive, GiveWin, and Aremos TSD files through the same interface provided for EViews databases. For example you can open a RATS file and copy-and-paste series into an EViews workfile or database. All EViews database operations, reading, writing, querying, etc., can be applied to these file formats.

Enterprise Edition Support for FAME, DRIBase, and Haver Analytics Databases

As part of the EViews Enterprise Edition (an extra cost option over EViews Standard Edition) support is provided for proprietary data formats of commercial data and database vendors. You can access FAME local and server based databases, Standard and Poors DRIBase databases, and native Haver Analytics DBX databases. The same, easy to use, EViews database interface has been extended to these data formats.

Remote Data Access

In addition to local databases, EViews has the ability to query and access data from remote databases via the Internet. Initially, remote access is only available to databases hosted by Standard & Poor's/DRI. In the future, software will be available from QMS that will make it possible for anyone to host a remote database.

Frequency Conversion

When you import data from a database, they are automatically converted to the frequency of your current project. EViews has options for frequency conversion, as well as support for the conversion of daily and weekly data. Series may be assigned a preferred conversion method, allowing you to use different methods for different series without having to specify the conversion method every time a series is accessed.

File Import and Export

EViews provides extensive read/write support for foreign files including ASCII text files, Excel .XLS files, Lotus .WK1 and .WK3 files and TSD files. In EViews, ASCII reads have been extended so you can precisely specify which characters should be treated as delimiters, and what text should be treated as missing values. Reading of Excel files has also been extended to allow reading from particular named sheets, and support has been added for Excel 8 (Excel 97) spreadsheets.

Graphics

EViews supports a wide range of graph types including line graphs, bar graphs, pie charts, scatter diagrams, mixed line-bar graphs, high-low graphs, and scatterplots. A variety of options give you control over line types, color, border characteristics, headings, shading and scaling, including logarithmic scaling and dual scale graphs. Legends are automatically created and you can add labels in any scalable Windows fonts anywhere on your graph. Any number of graphs can be combined in a single graph for presentation.
Customizing a graph is as simple as dragging graphic elements around the screen. Want to change the characteristics of a legend or a text label? Just click on it and your options are immediately presented in easy to understand dialogs.
You can easily incorporate your customized graphs into other Windows applications using copy-and-paste, or by exporting Windows metafiles.

A Powerful Programming Language

Point-and-click is fine, but you feel more comfortable entering commands. Besides, you need programming tools and capabili-ties. Well, EViews is really two programs in one. In addition to its state-of-the-art windowing interface, EViews includes a powerful command language that allows access to all menu items.
Modeled loosely after the BASIC programming language but with new object-oriented extensions and matrix handling capabilities.EViews allows you to enter individual commands for immediate or batch execution. Your programs can make use of advanced capabilities such as looping and condition branching, as well as subroutine and macro processing. Matrix primitives, from simple multiplication and inversion, to more advanced procedures for Kronecker products, eigenvector solution, and singular value decomposition, provide you with the tools you need for solving most complex problems.

Windows On-Line Help

Need help? EViews provides a full Windows-style help system with index and search capabilities. In addition, the entire EViews User's Guide and EViews Command and Programming Reference are provided in Adobe PDF format (along with Adobe Acrobat Reader). Both manuals are extensively hypertext linked, making it easy to find the information you need.

What's new in Version 7.1?

EViews 7.1 provides powerful new features targeted at the development and use of tools which extend the functionality of EViews. These features should be of great interest to all EViews users, not only those who write EViews programs, but also those who wish to use routines written by others

At the heart of EViews 7.1 upgrade is a new easy-to-use EViews Add-ins infrastructure that provides seamless access to user-defined programs using the standard EViews command, menu, and object interface. Using Add-ins, you can add user-defined features of power and sophistication that are virtually indistinguishable from built-in features.

Add-ins offer you a exciting new way of running EViews programs. You may readily define Add-ins that augment the EViews language with user-defined commands, specify new menu entries for point-and-click program interaction, and display program output in standard EViews object windows.

Add-in packages are EViews programs that, when installed, look and feel like built-in EViews procedures. Packages may generally be run from the EViews object and Add-ins menu, or via commands. Once installed, add-in packages should require no user-modification.

Add-in Libraries are EViews programs that extend the EViews programing language by providing routines and tools that other programs, including other Add-ins, may utilize.

What's new in Version 7?

• Performance
  • Faster computation.
  • Multi-processor support.
• General EViews Interface
  • Customize the appearance of your EViews environment.
  • Enhanced drag-and-drop support.
  • Improved command window interface.
  • Improved graph options interface.
  • Updated global options interface.
  • Auto-update EViews from the web.
• Data Handling
  • New workfile data frequencies: high-frequency (Intraday) data, with full support for hours, minutes, and seconds frequencies, multi-year, bimonthly, fortnight,10-day, daily with an arbitrary range of days of the week.
  • Greatly enhanced support for strings, including new string and string vector objects, and an extensive library of new functions for creating and manipulating string lists, and improved programming support.
  • Now offers direct EViews support for connecting to, opening, querying, and importing from the FRED? (Federal Reserve Economic Data) database.
  • EViews now supports reading Excel 2007 files.
  • More powerful command line tools for reading foreign data into an existing workfile.
• Graphs
  • Graphs can now auto-update as the underlying data change.
  • Improved graph options interface.
  • Interactive observation and value display.
  • Improved control over formatting of dates in the observation scale.
  • Added control over date label positioning and two row labeling.
  • Enhanced control over date/observation axis grid line placement.
  • More flexible custom labels for the observation scale.
• Programming Support
  • Logging of program messages.
  • Multi-line commenting using the program file editor.
  • Greatly enhanced support for strings, including new string and string vector objects, and an extensive library of new functions for creating and manipulating string lists, and improved programming support.
  • Enhanced support for Text objects.
  • Extensions to programming syntax.
  • User-defined dialogs.
  • New object data members.
  • New general information functions.
• External Interfaces
  • External programs may use the new EViews OLEDB driver to read data stored in EViews workfiles (WF1) and EViews databases (EDB).
  • The new EViews Microsoft Excel Add-in offers a simple interface for reading data stored in EViews workfiles and databases from within Microsoft Excel.
  • Create scripts or programs that launch or control EViews, transfer data, and execute EViews commands.
  • Use EViews to interact with the powerful programming languages of MATLAB? and R.
• Econometrics and Statistics
• Computation
  • Interpolation (Linear, Log-linear, Catmul-Rom Spline, Cardinal Spline) is offered as a series procedure.
  • Whitening is now offered as a series or group procedure.
  • Long-run variances and covariances may be calculated from a series or group of series.
  • Variance ratio testing may be performed on a series.
  • Single equation tests for cointegration.
• Estimation
  • Improved single equation TSLS/IV and GMM estimation (featuring new LIML and K-class estimators).
  • Single equation Cointegrating Regression.
  • Generalized Linear Models.
  • New methods of specifying weighted least squares.
• Testing and Diagnostics
  • Expanded choice of coefficient covariance estimators for single equation regression models.
  • New set of post-estimation diagnostics for single equation regression models.
  • Additional test and diagnostic views for TSLS and GMM estimation