John Butler

12 Questions 5 Answers 0 Followers

Questions related from John Butler

Do you know of any guidelines around having a separate independent researcher perform data analysis who was not involved in intervention delivery?

This is in the clinical psychology field, but any research guidelines I could reference would be great! I believe there is a move towards this way of working: where someone who has no vested...

09 July 2021 4,306 3 View

When using in-text citations in a systematic review, should you differentiate between studies that you reviewed and references to wider literature?

If so, how to do this - with asterisks and then a subsection in the reference list? I don't see journals giving much guidance, but when you have 30+ studies this seems like a helpful thing to do -...

30 May 2021 2,638 3 View

Are effect sizes required when reporting a Linear Mixed Model? If so, how are they calculated?

I have undertaken an RCT and, given multiple irregular time-point measures of the DV, have used linear mixed models to analyse the results and include moderator/predictor variables. CONSORT is...

03 May 2021 7,023 6 View

How do you analyse the effect of a binary categorical predictor variable on a continuous outcome variable, in SPSS?

I am astounded how hard this has been to google! Even with quote marks, everything is coming back as logistic regression, but this is where the outcome is binary no? I'm looking for help on how to...

01 May 2021 9,060 3 View

What statistical test to use for an RCT with 2 groups, 1 continuous outcome (DV) but multiple time-points?

I'm aware that a t-test could be used between means at each time-point; but isn't it wrong to analyse each time point separately (increase type 1 error?). Do I have to include time in as a...

03 April 2021 3,090 5 View

How do you add categorical variables into a meta-regression model in STATA?

I have already done subgroup analysis, and identified a couple significant categorical covariates. I have run a meta-regression with my continuous covariates, nothing was significant. But I was...

20 February 2021 5,325 0 View

How do you interpret multiple meta-regression in STATA?

Please could someone recommend a resource that explains performing meta-regression with multiple moderators. I have read the STATA META ANALYSIS REFERENCE MANUAL, but this only gives examples of...

18 February 2021 7,644 1 View

What is the minimum number of studies in each category required for a multiple subgroup analysis to be viable in a meta-analysis?

Cochrane Handbook mentions subgroup analyses are only warranted if there are more than 10 studies (I have 28), and if they are distributed evenly among categories of subgroup. I am wondering if...

18 February 2021 3,847 4 View

RCT meta-analysis: calculating Hedge's g when there is significant difference in outcome at baseline between intervention and control group?

I think I understand now that you ignore the baseline (pre-test) data when calculating Hedge's g. Instead subtracting the intervention posttreatment mean from the control posttreatment mean and...

09 February 2021 6,592 2 View

How do you calculate Pooled Standard Deviation over two (or more) time-points?

I am looking to calculate hedge's g effect sizes for a psychological intervention. A similar paper talks about obtaining "effect sizes by subtracting the posttest mean of the comparison group...

04 February 2021 9,944 5 View

How do you incorporate a study that used non-parametric analysis into a meta-analysis where majority of studies used parametric?

I am calculating Hedge's g for effect sizes, so I am pulling means, SDs, and Ns, from each study. However, one study did a Mann-Whitney U test, and so reports Mean Rank, Sum of Ranks, U, Z, and r...

01 February 2021 1,437 5 View

How does an intention-to-treat analysis work regarding investigating effect of psychotherapy in reducing distress?

Suppose an RCT, with 30 participants in each arm. Group A receives CBT sessions, Group B as a waitlist control does not. Both groups complete a depression questionnaire measure at baseline, and...

23 January 2021 5,214 3 View