Message-ID: <DB6PR05MB322262C486099B5D4BDE9C17A0E50@DB6PR05MB3222.eurprd05.prod.outlook.com>
Date: 2019-06-19T13:11:45Z
From: CHAPPELL Francesca
Subject: [R-meta] convergence in Mada
In-Reply-To: <CAMU7UxEX+G7qj2KyO+0CyCWmxociaNAgVJbE0GkgYECrM4cuQw@mail.gmail.com>
On a related note, it can also be useful to profile the likelihood of the correlation coefficient - estimation of correlation coefficient can be particularly poor even when convergence is achieved.
Francesca
-----Original Message-----
From: R-sig-meta-analysis [mailto:r-sig-meta-analysis-bounces at r-project.org] On Behalf Of Philipp Doebler
Sent: 19 June 2019 13:59
To: James Meyer <outlook_655291802F3BAFF3 at outlook.com>
Cc: r-sig-meta-analysis at r-project.org
Subject: Re: [R-meta] convergence in Mada
Hi James,
I have rarely had convergence problems. There are three potential problems:
(1) Low number of studies (5 model parameters...) but mada throws a warning if I remember correctly.
(2) Little variance in the false positive rates and/or sensitivities.
Especially relevant if all studies have the same sensitivity of, say, 95%.
This can sometimes lead to a degenerate covariance matrix of the bivarate random effect.
(3) A perfect between study correlation of logit(sens) and logit(fpr). If there is any suspicion, calculate the correlation matrix with cov2cor.
Also have a look at all standard errors and confidence intervals. The recent simulation study of Vogelsang et al. (2018) discusses convergence issues of mada (and other packages).
Kind wishes,
Philipp
On Wed, Jun 19, 2019 at 2:32 PM James Meyer < outlook_655291802F3BAFF3 at outlook.com> wrote:
>
> How can you tell if convergence has been accomplished using the
> reitsma() function in mada ? Which package do you recommend using for
> DTA meta-analysis if you have a small number of studies?
>
> Sincerely
> James C Meyer
> Sent from Mail<https://go.microsoft.com/fwlink/?LinkId=550986> for
> Windows 10
>
>
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--
Prof. Dr. Philipp Doebler
Technische Universit?t Dortmund
Fakult?t Statistik
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