Data are the raw results of the investigation entitled; Phenotypic stutter steps in experimentally evolved multicellularity In this study, we carried out a NetLogo agent-based model simulation of the multicellular snowflake yeast growth. Populations characterization was conducted with a Coulter Counter multisize 4 and FlowCam 3. The populations studied were the genetically uniform diploid wild-type Saccharomyces cerevisiae Y55 strain clones, C1W8.1 and C1W8.2 multicellular evolved strains, constructed ACE2 gene knockouts, and strains containing the missense mutation (ACE2 c.1934 A>T). The population data represent the six independent isolates per strain in two different media, YPD and SD. Files: NetLogo Agent Base model: Netlogo Snowflake 3D.nlogo3d (model) and Data_NETLOGO_model.csv (data obtained from the model used in the paper). Coulter Counter size distribution data of all the populations: Counter_Counter_Raw_data.xls: Data from Saccharomyces cerevisiae Y55 strain clones, C1W8.1 and C1W8.2 multicellular evolved strains, constructed ACE2 gene knockouts, and strains containing the missense mutation (ACE2 c.1934 A>T) in YPD and SD at 24h growth. Coulter_Counter_Raw_data_heterozygous_contructions: Size distributions of the heterozygote construct knockout (ACE2/ace2Δ) and homozygous missense (ACE2/ace2Δ) in YPD and SD at 24h growth. FlowCam image data: FlowCamPicturesData.zip: Pictures generated by the FlowCam. Flow_Cam_Raw data.xls: FlowCam data from Saccharomyces cerevisiae Y55 strain clones, C1W8.1 and C1W8.2 multicellular evolved strains, constructed ACE2 gene knockouts, and strains containing the missense mutation (ACE2 c.1934 A>T) in YPD and SD at 24h growth. Date generated statistically: Biomadality_mixEM_data.xlsx: non-Gaussian bimodal distributions for Coulter Counter data multicellular strains. bootstrapped_means.csv: bootstrapped means from the Coulter Counter data to calculate the relative contributions to phenotypic variation. bootstrapped_vars.csv: bootstrapped variance from the Coulter Counter data to calculate the phenotypic noise. Heatmap_overlap_distributions_raw_data.csv: overlapping indexes (η) of the KDE distributions were computed using the R-package ‘overlapping’ from the Coulter Counter data.