The method of minimization for allocation to clinical trials

Scott, Norman; McPherson, Gladys; Ramsay, Craig R; Campbell, Marion K

doi:10.1016/s0197-2456(02)00242-8

Cited by 554 publications

(439 citation statements)

References 37 publications

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“…This will significantly decrease the administrative cost and computational process demand [7,8] that is needed as compared to the conventional methods. This is specifically relevant to the randomisations where all participants are identified before the start of assignment process, Table 2: Strata with more those participant, the one who were pulled out and the assignment of the remaining by flip of a coin.…”

Section: Discussionmentioning

confidence: 99%

“…Furthermore when the number of participants in a stratum is odd, the allocation based on flip of a coin will result in one arm having more of the participant with particular covariates that may result in imbalance of covariates between arms. On the other hand, the sequential assignment of all participant based on covariate adaptive methods [6,10] comes with an increased administrative cost due to more demand in the computational process [7,8]. This brings unnecessary complexity when all participants are identified before the start of randomisation.…”

Section: Discussionmentioning

confidence: 99%

“…While in the study by Taves (1974) [6] the participant was assigned to the group with the lower total covariate to minimize imbalance, Pocock and Simon [10] proposed assigning participant to the group which prospectively creates less absolute differences of covariates if the participant was assigned to that group. Despite the advantages of covariate adaptive randomisation, the technique comes with an increased administrative cost due to more demand in the computational process of assignment [7,8].…”

Section: Introductionmentioning

confidence: 99%

“…Another method known as covariate adaptive randomization [6] has been commonly used when participants are not all identified before the start of randomisation [7]. In this method of randomisation, a new participant is assigned to a group in a sequential order through minimising the imbalance of several covariates between groups [8,9]. While in the study by Taves (1974) [6] the participant was assigned to the group with the lower total covariate to minimize imbalance, Pocock and Simon [10] proposed assigning participant to the group which prospectively creates less absolute differences of covariates if the participant was assigned to that group.…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

A Combined Technique for Randomisation of a Small Number of Participants with a Variety of Covariates into Treatment and Control Groups in Randomised Controlled Trials

Naemi

Healy²,

Sundar³

et al. 2014

J Clin Trials

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

A Combined Technique for Randomisation of a Small Number of Participants with a Variety of Covariates into Treatment and Control Groups in Randomised Controlled Trials

Naemi

Healy²,

Sundar³

et al. 2014

J Clin Trials

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“…Pocock and Simon's minimization method and Zelen's balancing method enable the balancing of each confounding factor (variable) between and among treatment subgroups over the entire duration of the trial [13][14][15][16][17]. The method was used increasingly in the 1990s due to the availability of computer programs [9].…”

Section: Minimization Programmentioning

confidence: 99%

Second-order interactions with the treatment groups in controlled clinical trials

Shiao

Ahn

Akazawa

2007

Computer Methods and Programs in Biomedicine

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SummaryThe occurrence of significant second-order interactions for group characteristics was examined using real data in a randomized controlled trial (RCT). The interactions exist in all RCTs; they could be easily overlooked when using the simple randomization or stratification methods, but could become more obvious when minimization methods are used. Using real data from an RCT, the minimization method enabled balancing the distributions of the four selected stratified factors. Analyses for 3-way second-order interactions including 6 additional potential confounding variables (for a total of 10 variables) presented 8 significant second-order interactions with the treatment groups. Interaction effects need to be evaluated when treatment effects are examined to maximize the power of the treatment effects in any RCTs. A stepwise regression method with piecewise linear functions would be useful to select the significant variables with interaction effects affecting the treatment outcomes in RCTs. Additional ways to handle interaction effects in RCTs are presented in this paper.

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Occlusive vs Gauze Dressings for Local Wound Care in Surgical Patients

Ubbink

Vermeulen²,

Goossens³

et al. 2008

Arch Surg

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Patients: Two hundred eighty-five hospitalized surgical patients with open wounds. Intervention: Patients received occlusive (ie, foams, alginates, hydrogels, hydrocolloids, hydrofibers, or films) or gauze-based dressings until their wounds were completely healed. Main Outcome Measures: Primary end points were complete wound healing, pain during dressing changes, and costs. Secondary end point was length of hospital stay. Results: Time to complete wound healing did not differ significantly between occlusive (median, 66 days; interquartile range [IQR], 29-133 days) and gauze-based dressing groups (median, 45 days; IQR, 26-106 days; log-rank P=.31). Postoperative wounds (62% of the wounds included) healed significantly (P=.02) quicker using gauze dressings (median, 45 days; IQR, 22-93 days vs median, 72 days; IQR, 36-132 days). Median pain scores were low and similar in the occlusive (0.90; IQR, 0.29-2.34) and the gauze (0.64; IQR, 0.22-1.95) groups (P=.32). Daily costs of occlusive materials were significantly higher (occlusive, €6.34 [US $9.95] vs gauze, €1.85 [US $2.90]; P Ͻ .001), but nursing time costs per day were significantly higher when gauze was used (occlusive, €1.28 [US $2.01] vs gauze, €2.41 [US $3.78]; PϽ .001). Total cost for local wound care per patient per day during hospitalization was €7.48 (US $11.74) in the occlusive group and €3.98 (US $6.25) in the gauze-based group (P=.002). Conclusions: The occlusive, moist-environment dressing principle in the clinical surgical setting does not lead to quicker wound healing or less pain than gauze dressings. The lower costs of less frequent dressing changes do not balance the higher costs of occlusive materials.

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The method of minimization for allocation to clinical trials

Cited by 554 publications

References 37 publications

A Combined Technique for Randomisation of a Small Number of Participants with a Variety of Covariates into Treatment and Control Groups in Randomised Controlled Trials

A Combined Technique for Randomisation of a Small Number of Participants with a Variety of Covariates into Treatment and Control Groups in Randomised Controlled Trials

Second-order interactions with the treatment groups in controlled clinical trials

Occlusive vs Gauze Dressings for Local Wound Care in Surgical Patients

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