# Questions tagged [canonical-correlation]

Canonical correlation analysis (CCA) is a method to analyze correlations between two sets of variables. It finds linear combinations of variables in each set such that their correlation is maximal.

144 questions
Filter by
Sorted by
Tagged with
18 views

I'm doing a canonical correlation analysis using scikit-learn's CCA. After doing the usual steps and calling ca.x_loadings_, I see that I get values bigger than 1. ...
• 21
21 views

### Is there a way to perform a Hierarchical Partitioning with NMDS in R?

I performed non-metric multidimensional scaling (NMDS) on my ecological data and I was satisfied with my results, but I was told that I should use hierarchical partitioning in my analysis to check for ...
• 11
64 views

### "RV coefficient" relationship to canonical correlation

Canonical correlation addresses the following: Given matrices $X$ and $Y$, what linear combination of the columns of $X$ best correlates with what linear combination of the columns of $Y$, and what ...
• 64.7k
7 views

### Using the jackknife method in permutation tests

We aim to employ a permutation test to evaluate the significance of the relationship between two datasets using Sparse Canonical Correlation Analysis (SCCA) for a specific level of sparsity. To ...
• 1
12 views

### What would it mean to have equal canonical coefficients (A,B) as a result of CCA?

I am using CCA to compare two matrices of n by m dimensions. ...
1 vote
38 views

### Extracted variance is above 1 (CCA and redundancy analysis)

I tried to repeat the analysis from Stewart and Love 1968, to compute the Variance Extracted and redundancy index from CCA. Based on their paper (if I followed it correctly), Variance Extracted per ...
10 views

### Determining an efficient index on sample sets

Context: I have an ever-growing data set of samples. (It consists of around $500$ samples currently.) Each sample in this set is an $m \times 3$ matrix where the $m$ rows represent $m$ different ...
• 306
1 vote
95 views

I'm trying to wrap my head around how to interpret the results of CCA. I've got a fairly deep understanding of OLS regression, and I've read a lot of helpful CCA explainers like this one by @ttnphns. ...
• 13
48 views

### Statistical analysis on cortisol reactivity (longitudinal)

I collected stress data (cortisol reactivity) on 4 timepoints. I also collected psychological measures at 1 timepoint. I would like to know if the psychological measure (one measurement time point) is ...
19 views

### incongruences between F-stats in the R cancor package

I'm using the R package candisc to perform canonical correlations. Since my dataset has missing values (only 36 rows without any NAs out of 88 rows total), I have two options: I can use the raw ...
• 33
1 vote
48 views

### Multiple group analysis in canonical correlation analysis

Canonical correlation analysis estimates the relationship between two canonical sets of variables. However, I am interested in using a technique to compare these CCA results across groups (something ...
26 views

### Canonical correlation analysis

I have data on variables such as age category, sex (3 categories), habits (each with a yes or no question), drug habits (each with a yes or no question), and osteoporosis index (oi) as continuous ...
1 vote
288 views

### What is the difference in interpretation between adding ellipse.type = "confidence" in PCA biplots?

I am trying to identify if three groups of species (like here) overlap or seperate out. I tried a popular method to identify ellipses: ...
• 111
1 vote
63 views

### Standardized and unstandardized canonical correlation coefficients

What exactly are the standardized and unstandardized canonical correlation coefficients and what is the difference between them?
• 11
725 views

### How to calculate Pearson correlation coefficient of two 3-dimensional features?

The book I read, Applied Predictive Modeling Textbook, mentions: Even though, single features do not correlate with each other, sets of features can correlate with other sets of features. I have an ...
• 313
1 vote
644 views

### Interpreting results of the vegan anova.cca function

1st question here! I've scoured the internet, including the vegan documentation, but am still confused about the meaning of the F versus ChiSquare values in the results of the anova.cca() vegan ...
219 views

### What's the difference between a CCA analysis and PCA with ellipses?

I have a data set with abundace of 4 species (S. spp, in bright colours here) across 72 sites and corresponding temperature, pH, altitude, moisture. First, I performed a CCA where ...
• 603
1 vote
316 views

### Post-hoc pairwise comparison in anova.cca (package vegan)

Is there a way to perform a post-hoc pairwise comparison following anova.cca, for categorical independent variables with >2 levels, in the same sense as ...
125 views

### Applications of Canonical Correlation Analysis in real-life problems?

I have been exposed to Canonical Correlation Analysis (CCA) a few years ago and I still find it mathematically elegant and beautiful. On Cross Validated there are several interesting posts on CCA, ...
1 vote
2k views

### What is the difference between a PCA, RDA and CCA analysis?

I am trying to understand the difference between a PCA, RDA and CCA analysis. Here is an example of a CCA triplot. It seems that a PCA + RDA = CCA plot. Here it's a CCA triplot, which incorporates one ...
• 603
47 views

### Finding the vectors/modes "maximally responsible" for the fluctutation of a quantity?

I have a question which I fear might be simple but i am completely unable to figure out. Lets say we have a time-series of a vector of coordinates which define a molecule ( column vector of x,y,z) ...
• 1
145 views

### CCA in feature selection [R]

I'm trying to conduct feature selection based on the Canonical Correlation Analysis (CCA). As far as I know, for two given datasets $X$ and $Y$ CCA looks for the linear projections of $X$ and $Y$ such ...
• 390
1 vote
45 views

### Canonical Correlation Analysis and Incorporating New Data

For some context, I am trying to follow this neuroscience paper (https://www.nature.com/articles/nm.4246?TB_iframe=true&width=921.6&height=921.6) Regarding my data, I have 2 datasets, one as a ...
• 335
1 vote
371 views

### Spread of species and site scores in R (vegan) DCA ordination

I have performed a Detrended Correspondence Analysis on social survey answers, aiming to see the spread of answers to 25 interview questions and how they related to the three farmer types (n =45) we ...
1 vote
63 views

### Multiview CCA with one source set and multiple independent target sets

I have 5 datasets from the same subjects that can be interpreted as different data modalities for these subjects. 4 of these datasets describe brain-related data and the last one contains behavioral ...
623 views

For my current project I am using sklearn.cross_decomposition.CCA. On several wepages (e.g. https://stats.idre.ucla.edu/r/dae/canonical-correlation-analysis/ or ...
135 views

### Why the correlation in CCA can be greater than 1? [closed]

I am working with the following paper https://home.ttic.edu/~klivescu/papers/andrew_icml2013.pdf where they use DCCA and in the results they present they show correlations between different sets of ...
• 21
1 vote
111 views

### Why is the first canonical direction equal to the left singular vector i.e. why is $w_1 = a = u_1$ in CCA (Canonical Correlation Analysis)?

I want to understand why the canonical direction $a$ is equal to the left singular value of $M = \Sigma^{-1/2}_X \Sigma_{X, Y} \Sigma^{-1/2}_Y$ and not $a = \sigma_1 u_1$. My calculation tell me that ...
• 6,916
74 views

### Maximization of correlation coefficient. The canonical correlation

The idea of the Canonical correlation is to maximize the correlation between two vectors $(Y,X)$ using 2 vector of weights $(\alpha,\beta)$. My problem is that I have a dependent variable $Y$ and a ...
73 views

• 2,496
125 views

### I'd like to do regression using canonical correlation analysis

I got two multidimensional datasets, X and Y. I thought I build the model, which explains the relationship between two datasets, using canonical correlation analysis (CCA). The first correlation ...
1 vote
2k views

### Canonical Correlation Analysis (CCA) - do you need to scale the input variables?

I am learning CCA and I have come across a question that I do not know how to answer. Suppose we have the following 2 sets of variables: ...
• 131
195 views

### Are there random matrix results like Marcenko-Pastur, but for CCA?

The Marcenko-Pastur law is about asymptotic distributions of eigenvalues. It starts from a simple null model (iid zero-mean Gaussian entries) and derives a distribution for the spectrum. In PCA, this ...
• 5,219