Message/Author 

Estee posted on Wednesday, October 16, 2013  6:22 am



Hi, I tested a mediation model. The indirect effect was bootstrapped. The 95% confidence limit was [.000, .038]. According to literature, an indirect effect is considered sig. if the CI does not include/cross zero. Is the .000 showed in the results really equal to zero or it may be for example.0001 ? so, how to confirm whether the 95% confidence limit [.000, .038] is sig or not? Thanks very much. 


I would count that as non significant even if the value was .0001. With so many tests being performed, I would be conservative. 

Joao Garcez posted on Friday, March 13, 2015  10:27 am



Hi, I was wondering something similar. I have a nonsignificant indirect effect (b = .019, p>.05) with the following bc bootstrap 95% CI: ( .047  .002 ). Is a value of .002 considered to be equal to zero? Also, when values in the lower and upper bound have opposite signs like the one above, does it mean something? The path above is negative with a positive value in the CI. Does it mean is nonsignificant? Thank you very much. JÁ 


If the CI covers zero, the coefficient is deemed insignificant. Your lower limit is negative and your upper limit positive, so your coefficient is nonsignificant. 

Joao Garcez posted on Tuesday, March 17, 2015  2:34 am



Thank you for the clarification. Best, JA 


Hi there, I too have a similar query  I have a nonsignificant indirect effect (B = 0.153, p = .104), but then the 95% BCa CI is [0.032 , 0.417]. I'm a but confused as to whether this is a significant mediation or not  the CI would suggest yes, but the p value no? Would appreciate any advice  many thanks! RE 


If the confidence interval and pvalue do not agree, you must not have a symmetric confidence interval. 


Thank you for the very quick response! I would agree that the confidence interval is asymmetric  looking at my data, the point estimate doesn't sit in the centre of the BCa confidence interval. Does this mean that it is not meaningful to interpret this in the normal way, i.e. 0 not being between the lower and upper bounds of the confidence interval as a sign of significant mediation? Many thanks for your helpful advice. RE 


The nonsymmetric CI is interpreted the same way: If 0 is not within the interval then the effect is significant. 

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