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Questions tagged [augmented-dickey-fuller]

A test of the [null] hypothesis that a time series has a unit root (ie, that it is non-stationary).

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Dickey-Fuller test interpretation (urca package)

I am having trouble with interpreting the Dickey-Fuller test on a time series using the ur.df() function in the urca package. I already read this thread but still need some advise. The command is: ...
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First or second difference or log for simulated real GDP data?

For a paper I need to use simulated real GDP data to regress this on average income mobility (how much more the next generation earns). As a hint the assignment indicates that the STATA code for a ...
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How many lags to use in ADF test?

So I've ran a ADF test on my data multiple times with different lags and all up to a lag of 4 have a p-value below .05. So in this case how many lags do you decide to use? Could this also provide a ...
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Unit Root Testing

I am having some troubles with the unit root test. The are some concepts that I do not fully understand. Could you please tell me if what I write in the following four passages is correct? I am new to ...
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Super confused about dfuller

I have a rather small dataset and just performed DFuller test for unit root. When testing with zero lags, it contains unit root. When using one lag, it does not contain unit root. However, when ...
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STATA: Demean and Detrend after Dickey-Fuller do not reduce p-value to insignificant levels

Please see below the process I have followed in STATA and help me understand whether I have done it correctly. The issue is that after de-mean-ing and de-trend-ing time-series (after Dickey-Fuller) ...
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Are all non-stationary series random walks?

Are all (non-explosive) time series either stationary around a deterministic trend or random walks? If I run the ADF test and I can't reject the null of non-stationarity does it imply the series is ...
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How Do I Interpret This Table When Testing For A Unit Root?

I'm testing data for unemployment in Poland for the presence of a unit root. I used NumXL (integrated into Excel) to perform an ADF test, which produced the table shown in the picture attached. How ...
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Does stationarity have to be satisfied for a time series regression problem?

I am recently trying to build a time-series regression model to predict for the output flow rate of a reactor given some upstream conditions. The reactor behaves quite cyclically because the ...
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How does one evaluate a null hypothesis of an absolute value of a parameter?

Say I am evaluating a null hypothesis such that H0: |p| = 1 Ha: |p| < 1 And want to understand how this differs in implementation and evaluation from the test: H0: p = 1 Ha: p < 1 Is this ...
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Stationary data, ADF test and interpretation, first difference ,OLS regression?

I am currently working my master's thesis and am studying bitcoin price determinants using OLS regression. My statistics level is quite beginner level. I have gave stationary tests a go however I am ...
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Is detrending equivalent to differencing?

Given a non-stationary time series, there are many statistical tests (e.g. ADF, KPSS, etc.) to test whether the series has unit root or not. Equivalently, they test whether a trending time series has ...
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What is the reasoning for using ADF test with trend or drift?

When people carry out ADF tests they are mostly preparing a time-series for analysis (in an ARIMA, VAR or whatever model). In that case I fail to understand why one would use tests with trend. If ...
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eviews augmented dickey fuller lag selection

Can someone tell me how does eviews calculate teh optimal Schwarz lag selection? I did a quick search this https://en.wikipedia.org/wiki/Bayesian_information_criterion is this the same method that ...
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Why do the Dickey-Fuller test and Lo-MacKinlay Variance Ratio test yield such different outcomes?

It is my belief that a unit root implies a random walk, but not vice versa. Therefore, would one not expect the Dickey-Fuller test to find non-stationarity in the same cases as the Lo-MacKinlay ...
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Q: Implications of autocorrelation in a Dickey-Fuller unit root test

I am conducting a Dickey-Fuller unit root test on the FEDFUNDS series from the FRED database. My estimation period is quarterly from 1955(1) to 2007(4) (taking the average of the monthly rates within ...
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Are trend-stationary series I(0)?

I have time-series of different interest rates. Graphs of all series show existence of trend. For some of these series ADF-test with constant rejects null hypothesis. For others, null hypothesis is ...
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What should I conclude if a Unit Root Test gives contradictory results with & without a trend?

I have a data set for a variable, for which I have run some unit-root tests: ADF (constant/without trend): t-stat=-1.0816, p-val=0.7218 - DNR ADF (constant & trend): t-stat=-4.5203, p-val=0.0021 -...
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In Cointegration, adf test or for VAR models. What makes difference in having trend + Constant, Constant alone, and non

In Cointegration, adf test or for VAR models. What makes difference in having trend + Constant, Constant alone, and non. in below link http://www.econ.uiuc.edu/~econ508/R/e-ta8_R.html It said ...
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Stationarity test for autocorrelation

can we use unit root test of residual to detect autocorrelation in a time series model? Are stationarity of the residual means there is no autocorrelation?
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Are there phi2 phi3 statistics for the DF-GLS unit root test?

It's known that there are phi 2 and phi 3 statistics when performing ADF unit root tests. These statistics tell us the correct specification of the model (Trend, constant, or none). When running ADF ...
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Why do we add $\delta_i \Delta Y_{t-i}$ in order to make an ADF test?

Let's say we have the ADF test for no constant and no deterministic trend. So the regression model is $$\Delta Y_t=\delta Y_{t-1}+\sum_{i=1}^{p-1} \delta_i \Delta Y_{t-i}+Z_t$$ according to https://en....
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Replicating Dickey Fuller? How did they know something was wrong? [cross posted on QF] [closed]

I am interested in testing if there is size distortion through simulations. I have recently been interested in replicating Dickey and Fuller (1979) and this source from another post helped a lot, here ...
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Dickey fuller to estimating other biases, intution needed

I have recently been working on replicating the Dickey-Fuller critical values i.e. generating the Dickey-Fuller test distribution. However, I would appreciate some intuition on this and some advice ...
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Stationarity tests

It is generally accepted that ADF is the most common test to check whether a time series has a trend or not. My question is: What if we just regressed the values of the dependend variable on their ...
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stationarity and fractional differencing

This is a methodology question. I would like to make the data stationary but not transform it "too much" (information loss), before it is fit for statistical/ML purposes such as regression or PCA. ...
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Model identification from Eviews Dickey-Fuller test output

So our econometrics professor gave us the following Eviews outputs. First, it asked if it was the right decision to differentiate twice, which, according to what I interpret from the Eviews display, ...
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Eviews : How to test for cointegration in the right way

I am studying ECM alone using a book and some parts are not explained. First, the book advise to test for a unit and for the order of integration of the series. In eviews options are not pretty clear ...
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Unit root in time series of log return of s&p 500. What to do? [closed]

I have 9500 closing prices of s&p500. I took daily return of the prices dailyreturn and then log return of the prices logreturn=log(1+dailyreturn). Now I checked the data using augmented Dickey-...
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How to deal with both stationary and non-stationary time series

I'm a bit frustrated since the time series I am trying to analyse right now has definitely non-stationary curve but it's last values differ greatly from the mean making the time series stationary. ...
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Making a time series stationary by demeaning

Tom's answer https://stats.stackexchange.com/a/7848/49691 to question How to make a time series stationary? highlights that: "If a series exhibits level shifts (ie change in intercept) the ...
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Unit Root - Real Interest Rate

I want to find out whether the real interest rate of different countries are non-stationary. The real interest rate is defined as the difference between the nominal interest rate and the inflation ...
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ADF test showing stationary for a non stationary series

I am running an ADF test in R on the following series: This to me is clearly non-stationary, but when I run the ADF test: ...
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Why is Dickey-Fuller test applied on the difference operator and not on the variable directly?

Why is not the Dickey-Fuller test applied directly on : $Y_t = \rho Y_{t-1} + u_t$ instead of : $\Delta Y_t = (\rho-1) Y_{t-1} + u_t$. Many papers apply the Dicker-Fuller on the first difference ...
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Grouping similar time series (clustering, cointegration)

I have a number of time series' that I am effectively trying to understand which are similar and which can be grouped together. I have some idea of what should be grouped with each other but I am also ...
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What are assumptions for the Augmented Dickey Fuller Test?

I am trying to use the Augmented Dickey Fuller test to see if the given time series data are stationary or not. As a dirty/quick method, I did the following: 1) plotted the time series data to see if ...
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ADF test and seasonal series

Hi I'm new in the time series field and so I've different doubts. Considering this dataset https://archive.ics.uci.edu/ml/datasets/Individual+household+electric+power+consumption And considering ...
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Stationarity in presence of an outlier

I am working on a bimonthly data where I have customer the customer's sales amount. I tried to plot the original series in python and the plot ...
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Interpretation of the ur.df() unit root test in R [closed]

I am a bit puzzled on how to interpret ur.df() function results in R. The test regression should be without drift or linear time ...
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Result of an ADF-Test compared with an estimated AR (p) model

I am currently investigating the inflation persistence for different countries by using R. I took data from the OECD for Sweden (1993-2017) and checked first if the series is stationary with the ur....
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Dickey-Fuller test for ARX models

I can't find any source that mentions whether or not the Dickey-Fuller test (or the augmented one) is suitable for an auto-regressive model with exogenous inputs. Is there any literature source for ...
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ADF contradiction with ACF

I have a daily price time series. If I plot the series and the ACF looks very non-stationar (Figure below). However the result of ADF says otherwise: ...
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Generalised superior ADF test misspecification

If I run an GSADF test of Phillips et al. (2015) to identify multiple unit-root periods, what I'm doing is basically hypothesis testing a recursive regression such as the following against the null $...
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Tests for stationarity give contradicting results

I have a time series consisting of 192 data points (12 years of monthly data). A simple plot (in my opinion) clearly indicates that the data are not stationary: However, when I do an ADF test I get a ...
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Unit root tests and correlation coefficients

A linear regression is performed as part of some unit root tests such as ADF, ADF-GLS (ERS), and PP. Should I pay attention to the correlation coefficients (ordinary, adjusted) of the regression? ...
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What does my ACF test tell me about numbers to use in ARMA?

Images I want to use an ARMA model for seasonally adjusted quarterly GDP growth figures and then check for structural breaks. I've run an ACF, PACF, kpss and adf test on the data I have, and you can ...
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Different number of observations and testing order of integration [closed]

Suppose I have a time-series in which I know it to be I(1), but I need to model it with fewer observations. And due to the low power of ADF test, fewer observations means testing the series to be I(0)....
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Spurious regression and autocorrelation?

I have calculated portfolio returns, using a zero cost strategy. I have data with monthly returns, that I try to explain with the Capital Asset Pricing Model (CAPM). That is, my dependent variable is ...
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Augmented Dickey-Fuller (ADF) test to test the stationarity of time series

A question in Time Series: We have Augmented Dickey-Fuller (ADF) test to test the stationarity of time series. But it seems that this test behaves weirdly. Even for time series which obviously look ...