# missing data

1. ### How to deal with missing values at the end of a time-serie?

Hi everyone! I have some problems concerning missing values in time-series data. I have 11 values for each subject, with values being hormone dosage at different time points (0, +40, +50, +55...). Some of these values are missing. I want to impute data and I have to use univariate, non...
2. ### Missing data-can a heterogenous small subgroup affect the outcome of analysis?

Hello everyone, I'm confronting an obstacle when doing clinical research, the problem is described as follows: There are 141 pieces of patients' data, and I want to use 2 formulas to analyze them. Formula A only needs 2 variables (Va, Vb), Formula B need 5 variables (Va, Vb, Vc, Vd, Ve). As you...
3. ### Novice: Statistical Analysis with few samples and missing data

Hello! Recently a colleague reached out asking for help wondering if there was any kind of statistic measure that could be used to evaluate some results. The results are given in the table below. NA - Not Available There are 9 observations, but only three have a category assigned because...
4. ### Partial Correlations with Missing Data

I have a dataset with incomplete/missing data and want to perform partial correlations in R. I realise that pcor.test does not allow missing data and partial.r does not show p-values of correlation coefficients. Is there any other command for partial correlations that a) allows missing data AND...
5. ### Critical n in order to reliably replace missing data with series mean?

I am looking for a good source that I can use as argument to replace missing data reliably with the series mean. I have a dataset (n=118) from which three datapoints are missing. 2 datapoints are missing within Variable X and 1 datapoint is missing within Variable Y. 2 datapoints are missing...
6. ### Rct efficicay for small sample

I have baseline and post-treatment questionnaire data on behavioural treatment and control groups. Each group has less than 10 participants. I have missing data both on baseline and posttreatment outcomes (10% of all values are missing). The data is missing completely at random. Do you have...
7. ### Does a reduced sample size after joining two datasets count as missing data?

Hi there, I have two datasets both share names which is what I use to join them together to form my sample on which I am running a logistical regression. However, after performing a fuzzy join I only have about 55% of the data matching (5.5k out of 10k observations). Does this count as missing...
8. ### System missing value

I have a data from 340 respondents that I key into SPSS. But the problem is the result of descriptive statistics show that the system have one missing data eventhough there is no data missing ( i filled up every single row and column). And SPSS say the total sample size is 341 instead of 340...
9. ### general approach to handle missing data while doing simulation

This is probably a naive question. I'm new to statistical simulation. So please be a little bit patient. I was just wondering, what are the general approaches to handle missing data fields while doing simulation? You can either add your own understandings or point me to some references or links...
10. ### Can iterative PCA be applied to grouped data?

My data set consist of 156 individuals with fifteen variables. The variables consist of one body mass (dependent) variable and fourteen (independent) variables of different bird bone dimensions (of one type of bone). The 156 individuals can be divided over 30 bird species, where some groups of...
11. ### Missing value imputation on a non-normal distribution - EM vs Regression? Or else?

Hi, Bit green when it comes to some of these methods, so please be gentle... but I'll try to provide as much info and concisely as possible. Any help sincerely appreciated. I have a non-normal dataset with missing at random data and am trying to determine which imputation method to use. I...
12. ### SPSS Statistics: Significant Differences between follow-up scores independent groups

Hi, I have collected data on scores for a sample population before, 1 year after and 6 years after an intervention. All participants in the sample received the intervention. However, participants required the intervention for different reasons. I want to find out whether there is a...
13. ### Missing data - seeking advice on approach!!

INTRO:Planning list wise deletion of missing data from large data set (7772). Data is from online survey, participation self-select. Q's could be skipped (none mandatory). Repeated measures resulted from 'select all apply' answer option on several q's - each option became an individual variable...
14. ### Comparing missing and non-missing subjects for dependent variables

Hello everyone. I am working with a data-set of a cohort study which has 3 different sets of paired data. For the third visit of the subjects, we have a lot of missing. So, I need to compare the basic characteristics (in the first and second visit) of the missing and non-missing subjects for my...
15. ### DIF Analyses with Missing Data

Hi all, I'm currently analyzing items from a bank for K-12 education. I have a separate data set for each grade/subject combination (for example, 1st grade English is a set, 2nd grade English is a set, etc). Each data set contains 400-7000(!) items. I would love to able to run various DIF...
16. ### How to handle missing data?

Hi, I just finished an online study in which participants filled out several questionnaires at baseline and after 6 weeks (posttest). There were two groups a control group and an intervention group. The intervention group received online treatment and control group was a waiting list...
17. ### Trend analysis / regression model with missing data

Hi, I want to apply a Poisson GLM to count data, analyzing trends. However, there are missing counts (i.e. missing values in the outcome variable) in the dataframe. Is there any recommended method how to deal with this? I know there exists "multiple imputation methods" to fill the gaps in the...
18. ### Combining missing information of duplicate cases

Hi I have a problem with a very large dataset (containing more than 20000 cases and about 350 variables). This dataset contains many duplicate cases of which in some rows some information is missing. What I need to do is to join information from duplicate rows with the same unique identifier...
19. ### How to handle missing values in lm.fit?

Is there a way to use lm.fit without completely removing rows with missing data using R? Is there a way for lm.fit to leave out one piece of missing data but compare the rest? I've tried all of the na.actions and can't seem to find one that works. Any help is appreciated. Thanks!
20. ### Question Regarding Missing Data

Hello everyone, I have several surveys completed with over 2000 participants. Some of the participants did not answer some of the questions (e.g. "Missing data"). We discussed using Median calculations to account for missing data. In addition to this, for data entry, we indicated a "6" for...