Basic Analysis • Text Explorer • Text Explorer Platform Options • Text Analysis Options
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Text Analysis Options
The Text Explorer red triangle menu contains the following analysis options:
Latent Class Analysis
Performs a latent class analysis on the binary weighted document term matrix using sparse matrix routines.
When you select Latent Class Analysis from the Text Explorer red triangle menu, a Specifications window appears with the following options:
Maximum Number of Terms
The maximum number of terms included in the latent class analysis.
Minimum Term Frequency
The minimum number of occurrences a term must have to be included in the latent class analysis.
Number of Clusters
The number of clusters in the latent class analysis.
See Latent Class Analysis.
Latent Semantic Analysis, SVD
Performs a sparse singular value decomposition of the document term matrix. See Latent Semantic Analysis (SVD).
Topic Analysis, Rotated SVD
Performs a varimax rotated singular value decomposition of the document term matrix to produce groups of terms called topics. See Topic Analysis.
Cluster Terms
Shows or hides a hierarchical clustering analysis of the terms in the data. To the right of the dendrogram, there are options to set the number of clusters and save the clusters to a data table. For each term, this data table contains its frequency, the number of documents that contain it, and its assigned cluster.
Cluster Documents
Shows or hides a hierarchical clustering analysis of the documents in the data. To the right of the dendrogram, there are options to set the number of clusters, save the clusters to a column in the data table, and show the documents in a selected branch of the dendrogram plot.
SVD Scatterplot Matrix
(Available after selecting Latent Semantic Analysis, SVD.) Shows or hides a scatterplot matrix of the term and document singular value decomposition vectors. You are prompted to select the size of the scatterplot matrix when you select this option. This scatterplot matrix enables you to visualize more than the first two dimensions of the singular value decomposition. The Show Text button opens a window that contains the text of the selected documents.
SVD Scatterplots of Document and Term Spaces
Topic Scatterplot Matrix
(Available after selecting Topic Analysis, Rotated SVD.) Shows or hides a scatterplot matrix of the rotated singular value decomposition vectors. The Show Text button opens a window that contains the text of the selected documents.
Singular Value Decomposition Specifications Windows
The analysis options in the Text Explorer platform are based on the Document Term Matrix (DTM). The DTM is formed by creating a column for each term in the Term List (up to a specified Maximum Number of Terms). Each text document (equivalent to a row in the data table) corresponds to a row of the DTM. The values in the cells of the DTM depend on the type of weighting specified by the user in the Specifications window.
SVD Specification Window shows the Singular Value Decomposition Specifications window. When you select options from the Text Explorer red triangle menu that perform a singular value decomposition on the document term matrix, the Specifications window appears with the following options:
Maximum Number of Terms
The maximum number of terms included in the singular value decomposition.
Minimum Term Frequency
The minimum number of occurrences a term must have to be included in the singular value decomposition.
Weighting
The weighting scheme that determines the values that go into the cells of the document term matrix. The weighting scheme options are described in Document Term Matrix Specifications Window.
Number of Singular Vectors
The number of singular vectors in the singular value decomposition. The default value is the minimum of the number of documents, the number of terms, or 100.
Centering and Scaling
Options for centering and scaling of the document term matrix. You can choose between Centered, Centered and Scaled, and Uncentered. By default, the document term matrix is both centered and scaled.
SVD Specification Window

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Help created on 9/19/2017