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Estimating the sample mean and standard deviation from commonly reported quantiles in meta-analysis

journal contribution
posted on 2020-09-01, 00:00 authored by S McGrath, X F Zhao, R Steele, B D Thombs, A Benedetti, B Levis, K E Riehm, N Saadat, A W Levis, M Azar, D B Rice, Y Sun, A Krishnan, C He, Y Wu, P M Bhandari, D Neupane, M Imran, J Boruff, P Cuijpers, S Gilbody, J P A Ioannidis, L A Kloda, D McMillan, S B Patten, I Shrier, R C Ziegelstein, D H Akena, B Arroll, L Ayalon, H R Baradaran, M Baron, A Beraldi, C H Bombardier, P Butterworth, G Carter, M H Chagas, J C N Chan, R Cholera, N Chowdhary, K Clover, Y Conwell, J M de Man-van Ginkel, J Delgadillo, J R Fann, F H Fischer, B Fischler, D Fung, B Gelaye, F Goodyear-Smith, C G Greeno, B J Hall, P A Harrison, M Harter, U Hegerl, L Hides, S E Hobfoll, M Hudson, T Hyphantis, M Inagaki, K Ismail, N Jetté, M E Khamseh, K M Kiely, Y Kwan, F Lamers, S I Liu, M Lotrakul, S R Loureiro, B Löwe, L Marsh, A McGuire, S M Sidik, T N Munhoz, K Muramatsu, F L Osório, V Patel, B W Pence, P Persoons, A Picardi, K Reuter, A G Rooney, I S Santos, J Shaaban, A Sidebottom, A Simning, L Stafford, S C Sung, P L Lynnette Tan, Alyna TurnerAlyna Turner, C M van der Feltz-Cornelis, H C van Weert, P A Vöhringer, J White, M A Whooley, K Winkley, M Yamada, Y Zhang
Researchers increasingly use meta-analysis to synthesize the results of several studies in order to estimate a common effect. When the outcome variable is continuous, standard meta-analytic approaches assume that the primary studies report the sample mean and standard deviation of the outcome. However, when the outcome is skewed, authors sometimes summarize the data by reporting the sample median and one or both of (i) the minimum and maximum values and (ii) the first and third quartiles, but do not report the mean or standard deviation. To include these studies in meta-analysis, several methods have been developed to estimate the sample mean and standard deviation from the reported summary data. A major limitation of these widely used methods is that they assume that the outcome distribution is normal, which is unlikely to be tenable for studies reporting medians. We propose two novel approaches to estimate the sample mean and standard deviation when data are suspected to be non-normal. Our simulation results and empirical assessments show that the proposed methods often perform better than the existing methods when applied to non-normal data.

History

Journal

Statistical methods in medical research

Volume

29

Issue

9

Pagination

2520 - 2537

Publisher

Sage

Location

London, Eng.

ISSN

0962-2802

eISSN

1477-0334

Language

eng

Publication classification

C1 Refereed article in a scholarly journal