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Unanswered Questions

5,900 questions with no upvoted or accepted answers
20 votes
0 answers
2k views

Implementation of CoVaR (a systemic risk measure) in R

I'm trying to estimate CoVaR using bivariate DCC GARCH in R. The concept of CoVaR is the dependence adjusted of VaR, which was first introduced by Adrian and Brunnermeier (2011). However, this ...
18 votes
0 answers
14k views

Time series regression with overlapping data

I am seeing a regression model which is regressing Year-on-Year stock index returns on lagged (12 months) Year-on-Year returns of the same stock index, credit spread (difference between monthly mean ...
16 votes
0 answers
447 views

What is tantile regression?

My question follows on this discussion of medials and tantiles vs medians and quantiles from earlier this year: When would we use tantiles and the medial, rather than quantiles and the median? As ...
14 votes
0 answers
700 views

Convolutional neural network for multi-variate time series?

I want to use CNN architectures for classification of multivariate time-series, where we apply one label to each sequence. I searched the net for the available designs in the literature and i found ...
13 votes
0 answers
415 views

Is autocorrelation not worth addressing with small N?

Consider a simple regression context in which there is a small set of response values, $Y$, and corresponding dates, $X$. (For simplicity, we can assume the dates are equally spaced.) We would like ...
12 votes
0 answers
2k views

Empirical Prediction interval for time series forecast based on quantile regression

As Gardner notes "almost all point forecasts are wrong", so prediction intervals (PI) are necessary to quantify uncertainty and help us make informed decisions. There exists theoretical PI, and in ...
11 votes
3 answers
2k views

Need advice on change point (step) detection

I have a time series with lots of steps/jumps (data file here). A plot is given below. I would like to subtract an appropriate value for each of these square wave features to bring them back down to ...
10 votes
0 answers
5k views

Stationary vs Stability

I am searching for an example of an unstable VAR($p$) process (its reverse characteristic polynomial has no roots inside and on the complex unit circle) which is stationary. I come up with this ...
9 votes
0 answers
116 views

Why don't we typically worry about stationarity in panel data models with fixed effects?

Why don't we typically worry about stationarity in panel data models with fixed effects? In time series analysis, stationarity is often a crucial assumption. However, I've noticed that in applied ...
9 votes
1 answer
2k views

PyMC3 implementation of Bayesian MMM: poor posterior inference

Google released a whitepaper on Media Mix Modelling (MMM) in 2017; vanilla MMM (established in the 1960s) uses multivariate regression. It's a decent mechanism to understand which of your marketing ...
9 votes
0 answers
982 views

Why does uncertainty of the autocorrelation coefficient increase as lag increases?

The Python module statsmodels contains functions for ACF and PACF. Below is an example from the docs with a plot that shows the (zero-centered) confidence ...
9 votes
1 answer
179 views

Is there a ML or DL tool that can learn to detect periodically occurring patterns in a one dimensional time series?

I am trying to create a tool that labels refrigerator temperature readings. A reading is taken every 5 minutes, and its label identifies whether of not it was taken while the refrigerator was ...
9 votes
0 answers
7k views

What is difference between interrupted time series and regression discontinuity design

Say that one has data over time, t, on an outcome, y. There is an event that happens at t==0....
9 votes
0 answers
1k views

Fisher's test of periodicity

I have evenly sampled time series on which I applied Fourier transform. I am trying do determine if the signal contains statistically significant periodic components. I have succeeded with determining ...
8 votes
0 answers
290 views

Time series: sample vs. population + population vs. realizations of random process

Suppose we have $120$ monthly observations (Jan 2000 - Dec 2009) of unemployment rate and suppose we would like to use these in order understand the unknown underlying stochastic process that ...

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