# Articles by Keith Goldfeld

### Copulas and correlated data generation: getting beyond the normal distribution

June 18, 2017 |

Using the simstudy package, it’s possible to generate correlated data from a normal distribution using the function genCorData. I’ve wanted to extend the functionality so that we can generate correlated data from other sorts of distributions; I thought it would be a good idea to begin with binary ...

### When marginal and conditional logistic model estimates diverge

June 8, 2017 |

Say we have an intervention that is assigned at a group or cluster level but the outcome is measured at an individual level (e.g. students in different schools, eyes on different individuals). And, say this outcome is binary; that is, something happens, or it doesn’t. (This is important, ...

### It can be easy to explore data generating mechanisms with the simstudy package

May 16, 2017 |

I learned statistics and probability by simulating data. Sure, I battled my way through proofs, but I never believed the results until I saw it in a simulation. I guess I have it backwards, it worked for me. And now that I do this for a living, I continue to ...

### It can be easy to explore data generating mechanisms with the simstudy package

May 15, 2017 |

I learned statistics and probability by simulating data. Sure, I did the occasional proof, but I never believed the results until I saw it in a simulation. I guess I have it backwards, but I that’s just the way I am. And now that I am a so-called professional, ...

### Everyone knows that loops in R are to be avoided, but vectorization is not always possible

May 9, 2017 |

It goes without saying that there are always many ways to solve a problem in R, but clearly some ways are better (for example, faster) than others. Recently, I found myself in a situation where I could not find a way to avoid using a loop, and I was immediately ... [Read more...]

### Everyone knows that loops in R are to be avoided but vectorization is not always possible

May 4, 2017 |

It goes without saying that there are always many ways to solve a problem in R, but clearly some ways are better (for example, faster) than others. Recently, I found myself in a situation where I could not find a way to avoid using a loop, and I was immediately ... [Read more...]
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