Selecting Market Research Tools and Templates for Six Forces Research

This skill teaches you how to assemble a lean, repeatable toolkit of market research tools, scoring templates, and visualization formats that standardize your Six Forces analysis so every force is evaluated with consistent rigor and the output is immediately usable for strategic decisions.

Start by mapping the six data categories you need to populate: rivalry intensity, buyer power, supplier power, entry barriers, substitute threats, and complementary product dynamics. Then select one tool per function: a secondary research database for industry data, a spreadsheet or scoring template for standardized force ratings, and a visualization layer for presenting results. Prioritize tools your team already uses, because adoption friction kills consistency faster than feature gaps.

Outcome: You produce a configured, ready-to-use research toolkit consisting of a scored template, a data source inventory, and a visualization format that your team can reuse across multiple Six Forces analyses without reinventing the process each time.

Synthesized from public framework references and reviewed for accuracy.

MarketingBeginner2-3 hours

Prerequisites

  • Familiarity with the Six Forces Model framework and its six force categories
  • Basic spreadsheet proficiency (formulas, conditional formatting, charts)
  • Access to at least one industry data source (free or paid)
  • Understanding of your organization's strategic questions the analysis needs to answer

Overview

Every Six Forces analysis lives or dies on the quality of data feeding it and the consistency of how that data gets scored. Yet most teams skip the tooling step entirely, jumping straight into research with whatever browser tabs happen to be open. The result is predictable: force ratings that reflect which analyst happened to find a good source, not the actual competitive dynamics of the industry. Selecting the right market research tools before you begin collecting data is the operational foundation that makes a Six Forces Model analysis repeatable, defensible, and comparable over time.

This skill sits at the very beginning of the Six Forces workflow, before collecting data and well before synthesizing recommendations. Its job is narrow but critical: audit the data needs of all six forces, match those needs to specific tools and sources, build a scoring template that enforces consistent evaluation criteria, and choose a visualization format that communicates results to stakeholders who will never read the underlying spreadsheet. The concrete artifact you produce is a configured toolkit document that lists every tool, its role, access credentials or links, and the scoring template pre-loaded with your force definitions and rating scales.

Getting this right means the rest of the analysis flows faster and produces trustworthy output. Getting it wrong means you discover gaps three weeks in, when someone asks why buyer power was rated 'high' with no sourcing while supplier power has twelve footnotes. The toolkit levels the playing field across all six forces so that the complementary products force, which teams often shortchange because it is less familiar, receives the same analytical rigor as traditional rivalry assessment. You will finish this skill with a research kit you can hand to any analyst on your team and say, 'Start here.'

How It Works

The logic behind market research tools selection for a Six Forces analysis is layered matching. You are matching three dimensions simultaneously: data type to source, evaluation method to template structure, and output format to audience. Getting any one layer wrong creates friction that compounds through the entire analysis.

First, data type to source. Each of the six forces demands different categories of information. Rivalry intensity needs market share data, pricing trends, and competitor financials. Buyer power needs customer concentration ratios, switching cost estimates, and price sensitivity indicators. Supplier power needs input cost breakdowns, supplier count, and contract structures. Entry barriers need capital requirements, regulatory data, and brand strength proxies. Substitute threats need cross-elasticity signals, technology adoption curves, and adjacent market sizing. The complementary products force, unique to the Six Forces Model, needs ecosystem mapping data, integration dependency metrics, and co-adoption rates. No single market research tool covers all six. The toolkit must combine secondary research databases, public filings, industry reports, and sometimes primary research instruments.

Second, evaluation method to template structure. Raw data is useless without a scoring mechanism that translates qualitative findings into comparable ratings. The template must define what 'high,' 'medium,' and 'low' mean for each force, anchor those definitions to observable thresholds (for example, buyer power is 'high' when the top five customers account for more than 60% of revenue), and enforce a consistent scale. A 1-5 numeric scale with written anchors works better than pure labels because it forces granularity and makes averaging across sub-factors meaningful.

Third, output format to audience. A strategy team that meets weekly can absorb a detailed force-by-force spreadsheet. A board presentation needs a radar chart or heat map that communicates the overall shape of competitive pressure in under ten seconds. The visualization choice should be made upfront because it constrains how you structure the scoring template. If you know the final output is a radar chart, your template must produce a single composite score per force. If the output is a detailed brief, the template should preserve sub-factor scores.

The reason this matching process works is that it surfaces gaps before they become problems. When you explicitly list what data each force requires and then check whether your chosen tools can provide it, you discover blind spots while there is still time to fill them. Teams that skip this step and jump into ad hoc research invariably over-index on the forces they know best and under-invest in the ones that are less familiar, producing a lopsided analysis that confirms existing biases rather than revealing new strategic insight.

Step-by-Step

  1. Step 1: Audit data requirements for each force

    Create a six-row table with columns for force name, required data types, data granularity needed, and update frequency. For each of the six forces, list the specific data points that a credible assessment requires. Rivalry intensity might need market share percentages, average industry margins, recent M&A activity, and capacity utilization rates. Buyer power might need customer concentration data, average deal size, and switching cost estimates.

    Be specific about granularity: 'market share data' is too vague, 'market share by revenue for the top ten competitors in the North American segment, last three years' is actionable. Also note how current the data must be. Substitute threat data can sometimes be two years old. Pricing trend data for rivalry assessment should be within six months.

    This table becomes your shopping list for the tools you will select in subsequent steps.

    Tip: Interview the person who will present the final analysis and ask them which forces they expect pushback on from stakeholders. Those forces need the most granular and defensible data, so note them as 'high evidence' requirements in your table.

  2. Step 2: Inventory your existing tools and data access

    Before shopping for new market research tools, catalog what your organization already has. Check for subscriptions to industry databases like IBISWorld, Statista, S&P Capital IQ, or PitchBook. S. Census Bureau, Eurostat, or SEC EDGAR.

    Look at internal data: CRM exports that reveal customer concentration, procurement records that show supplier dependency, product analytics that indicate feature adoption patterns relevant to complementary product analysis. For each existing resource, note what force or forces it can feed, what its limitations are (geography, recency, depth), and who on the team knows how to use it. The goal is to avoid purchasing redundant tools and to identify the true gaps. Most organizations have 60-70% of what they need already, scattered across departments.

    Tip: Check with your finance, procurement, and product teams individually. They often have database access or internal datasets they do not advertise because nobody from strategy has ever asked.

  3. Step 3: Select tools to fill identified gaps

    Compare your data requirements table from Step 1 against your inventory from Step 2. The gaps are your actual shopping list. ). Prioritize tools that cover multiple forces.

    A good industry report platform might feed rivalry, buyer power, and entry barrier assessments simultaneously. For the complementary products force, you may need ecosystem mapping tools or platform analytics that traditional market research databases do not cover. Avoid selecting more than four or five tools total. Every additional tool increases the coordination burden and the chance that one analyst skips it.

    Tip: If budget is a constraint, pair one paid database for quantitative data with free sources like Google Scholar for academic research on industry dynamics, company investor presentations for competitor strategy signals, and trade association reports for market sizing.

  4. Step 4: Design the scoring template

    Build a spreadsheet template with six tabs, one per force. Each tab has a consistent structure: a list of sub-factors on the left (3-6 sub-factors per force), a 1-5 rating scale with written anchors for each sub-factor, a weight column if some sub-factors matter more, a weighted score column, a data source column where the analyst records which tool or report provided the evidence, and a notes column for qualitative context. Write the rating anchors explicitly. ' These anchors are what prevent score drift between analysts and between quarterly updates.

    Include a summary tab that pulls composite scores from all six force tabs and feeds the visualization.

    Tip: Use conditional formatting to color-code scores automatically: green for 1-2 (low threat/power), yellow for 3, red for 4-5 (high threat/power). This turns the raw spreadsheet into a visual heat map without any additional tools.

  5. Step 5: Define the visualization format

    Choose a primary visualization for the final output before anyone starts researching. The three most common formats for Six Forces output are radar charts, heat maps, and force summary dashboards. Radar charts work best when you want to compare your industry's force profile against a different time period or a different market. They require a single composite score per force (which your template's summary tab should produce).

    Heat maps work best when stakeholders need to see sub-factor detail at a glance. Force summary dashboards combine a radar chart with brief narrative per force and are the most complete but also the most time-consuming to build. Select the format based on your audience. A quarterly strategy review typically needs a radar chart with supporting narrative.

    A one-time market entry assessment benefits from the full dashboard. Configure your chosen format as a template file or slide template now, with placeholder data, so that populating it later is a matter of copying final scores rather than designing from scratch.

    Tip: Build the visualization template with dummy data that represents a plausible but clearly fictional industry. This forces you to verify that every score flows correctly into the chart before real data is involved, and it gives stakeholders a preview of what the final deliverable will look like.

  6. Step 6: Create a source citation protocol

    Decide how your team will document where each data point and each rating came from. This sounds bureaucratic but it is the single biggest factor in whether the analysis survives stakeholder scrutiny. Define a standard citation format that includes source name, publication date, the specific figure used, and the page or URL where it was found. Embed this format into the 'data source' column of your scoring template so analysts fill it in as they go rather than trying to reconstruct it after the fact.

    For primary research inputs (like interviews or surveys), define what constitutes a citable source: minimum sample size, who was interviewed, and date of the conversation. A Six Forces analysis that cannot point to specific evidence behind each score will be challenged in every review meeting and eventually abandoned.

    Tip: Add a 'confidence level' column next to the data source column with options of 'confirmed' (hard data from a reputable source), 'estimated' (extrapolated or triangulated from multiple weaker sources), and 'assumed' (team judgment with no external backing). This transparency helps decision-makers calibrate how much weight to put on each force score.

  7. Step 7: Test the toolkit with one force

    Before handing the toolkit to your full team, run a dry test by completing the analysis for a single force end to end. Choose a force you expect to have readily available data for, such as rivalry intensity, and walk through the entire workflow: pull data from your selected market research tools, enter it into the scoring template, assign sub-factor ratings using your written anchors, document sources, calculate the composite score, and populate the visualization template. Time yourself. Note where you hit friction: a tool that requires too many clicks to export data, a sub-factor whose rating anchors are ambiguous, a visualization template that does not correctly pull the composite score.

    Fix these issues now. This dry run typically takes 45-90 minutes for a single force and reveals 3-5 template or workflow problems that would have multiplied across all six forces if left uncorrected.

    Tip: Have a second team member independently score the same force using the same toolkit without seeing your ratings. Compare results. If your scores differ by more than one point on any sub-factor, the rating anchors for that sub-factor need tightening.

  8. Step 8: Document the toolkit and distribute

    Create a one-page toolkit overview document that lists every component: the scoring template (with a link to the file), each selected market research tool (with login instructions or access links), the visualization template (with a link), the citation protocol, and the assignment of which team member covers which force. Include a brief 'getting started' section that explains the workflow sequence: audit the data table first, collect data using the listed tools, score sub-factors in the template, document sources as you go, calculate composite scores, and populate the visualization. This document is the handoff artifact. Anyone picking up the project, including a new team member or an AI agent executing the research, should be able to read this single page and know exactly what to do, what tools to open, and where to put results.

    Tip: Store the toolkit document, scoring template, and visualization template in a shared folder with version control. Name files with a date stamp so that when you rerun the analysis next quarter, you can compare against the prior version and track how forces shifted.

Examples

Example: B2B SaaS startup entering the project management market

A 15-person SaaS startup is preparing a Series A pitch and needs a Six Forces analysis of the project management software market. The team has two analysts, a $500 annual budget for research tools, and two weeks to deliver results. They have access to a CRM with 200 customers and basic product analytics.

The team starts by auditing data requirements and discovers that rivalry data (market share, competitor count, feature comparison) is the most data-intensive force. They inventory existing resources and find they already have access to Statista through a university alumni benefit and can pull competitor pricing from public websites. For their $500 budget, they purchase a single month of a competitive intelligence tool that covers feature comparisons and estimated revenue for the top 15 competitors. They build a scoring template in Google Sheets with five sub-factors per force, each anchored to quantitative thresholds drawn from publicly available industry benchmarks.

The complementary products force is populated using their own product analytics data showing which integrations drive retention. They assign three forces per analyst with a shared deadline. The visualization is a radar chart in Google Slides with a one-paragraph narrative per force. Total setup time is three hours.

The dry run on rivalry intensity takes 75 minutes and reveals that one sub-factor, 'brand loyalty,' has ambiguous rating anchors. They rewrite it before distributing. The final analysis is completed in eight working days, and the radar chart becomes a recurring slide in their investor updates.

Example: Enterprise consulting firm analyzing the electric vehicle battery market

A strategy consulting team of six is conducting a Six Forces analysis for a Fortune 500 client evaluating entry into EV battery manufacturing. Budget for market research tools is effectively unlimited, but the engagement timeline is tight at four weeks, and the deliverable must withstand board-level scrutiny.

The team's data audit reveals that supplier power (lithium, cobalt, nickel sourcing) and complementary products (charging infrastructure, vehicle OEM partnerships) are the most complex forces requiring specialized data. They inventory firm-wide tool access and find S&P Capital IQ for financial data, Bloomberg for commodity pricing, and an existing subscription to a battery industry research service. The gap is in complementary product ecosystem mapping, for which they license a two-month subscription to an automotive industry platform with charging infrastructure data. The scoring template is built in Excel with a macro that auto-generates a composite score per force and feeds a PowerPoint radar chart via linked data.

Rating anchors are co-developed with the client's VP of Strategy to ensure they reflect the client's risk tolerance, specifically calibrating what level of supplier concentration they consider 'high' given their existing procurement capabilities. Each force is assigned to a two-person team. The dry run surfaces a problem: the commodity pricing data from Bloomberg uses different date ranges than the industry report data, making comparisons misleading. They standardize all data to trailing-twelve-month averages.

The final toolkit document includes access credentials for all six tools, the versioned scoring template, and a change log. The completed analysis is delivered as a 40-page report with a six-force radar chart on the executive summary page.

Example: Solo founder analyzing the local fitness studio market

A solo entrepreneur is considering opening a boutique fitness studio in a mid-sized city. There is no budget for paid market research tools. The founder has basic Excel skills and needs to make a go/no-go decision within one week.

The data requirements audit is simplified: rivalry data comes from Google Maps searches and Yelp listings to count competitors and assess density. Buyer power data comes from surveying 30 potential customers via a free online form about their willingness to switch gyms and price sensitivity. Supplier power is minimal (equipment suppliers, lease terms) and assessed from three vendor quotes. New entrant threat is evaluated using local commercial real estate availability and franchise expansion announcements found via Google News.

Substitute threat data covers at-home fitness app downloads and pricing from app store listings. Complementary products cover partnerships with nutritionists, physical therapists, and athletic apparel brands in the area, sourced through LinkedIn searches and local business directories. The scoring template is a single Google Sheet with one tab, six rows (one per force), four sub-factors each, and a 1-5 scale with one-sentence anchors. The visualization is a simple bar chart built into the same sheet.

' After recalibrating using per-capita ratios from Census data, the threshold becomes actionable. The entire toolkit setup takes 90 minutes, the analysis is completed in five days, and the bar chart becomes the centerpiece of a one-page decision memo.

Example: Corporate innovation team benchmarking across three geographic markets

A multinational consumer goods company wants to compare competitive dynamics across the US, EU, and Southeast Asian markets for its snack food division. Three regional teams will conduct parallel Six Forces analyses that must be directly comparable. The teams have different tool access and different levels of familiarity with the framework.

The central innovation lead recognizes that comparability is the primary risk, not data quality in any single region. She starts by building a master scoring template with sub-factors, rating anchors, and data source requirements that are industry-specific but geography-agnostic. For example, 'buyer power' sub-factor thresholds are defined as percentage-of-revenue concentration rather than absolute revenue numbers, so they apply regardless of market size. She audits each regional team's tool access and finds that the US team has Nielsen, the EU team has Euromonitor, and the Southeast Asia team has a regional trade association database.

Rather than forcing all teams onto one platform, she creates a data normalization protocol that specifies the exact output format each team must deliver: a CSV with standardized column headers. The visualization is a side-by-side radar chart with three overlaid profiles (one per region) in a shared PowerPoint template. The dry run is conducted with the US team first, and it reveals that 'substitute threat' sub-factors need a region-specific modifier because substitute products differ dramatically (health bars in the US, street food in Southeast Asia). She adds a 'regional context' notes field to the template.

All three teams complete their analyses in parallel over three weeks, and the final deliverable shows that Southeast Asia has materially lower entry barriers and higher complementary product opportunity than the other two markets, directly informing a market entry prioritization decision.

Best Practices

  • Standardize your rating scale across all six forces using the same 1-5 numeric system with explicit written anchors for each level. When one force uses a 1-3 scale and another uses 1-10, composite comparisons become meaningless. Inconsistent scales also introduce unconscious bias where analysts default to the middle of whatever range is available, compressing the spread of scores.

  • Limit your core toolkit to four or five tools maximum. Every additional tool increases the chance that an analyst skips it because they forgot, could not log in, or ran out of time. A compact toolkit with clear assignments produces more consistent output than an exhaustive list of twelve databases nobody fully uses. If a tool is not being used for at least two forces, it probably does not earn its place in the kit.

  • Pre-populate the scoring template with sub-factor definitions and rating anchors before distributing it to researchers. An empty template with just column headers invites interpretation drift, where each analyst invents their own definition of 'high' buyer power. Pre-populated anchors act as a shared calibration standard. The ten minutes you spend writing anchors saves hours of reconciliation later.

  • Choose your visualization format before starting data collection, not after. The visualization format determines what data resolution you need: a radar chart only needs six composite scores, while a detailed heat map needs 20-30 sub-factor scores. If you collect data at the wrong granularity, you either cannot populate your chosen visualization or you have surplus detail nobody requested.

  • Include a dedicated 'complementary products' section in your template with equal structural weight to the other five forces. Teams habitually under-resource this force because it is newer and less familiar. By giving it the same number of sub-factors, the same scoring structure, and the same data source requirements in the template, you architecturally prevent it from becoming an afterthought.

  • Build a source citation protocol into the template itself, not as a separate instruction document. When the citation field is physically adjacent to the score field in the same row, analysts fill it in as they score. When it is in a separate document, compliance drops below 40% by the third force. The best templates make it harder to skip the source than to fill it in.

  • Version-stamp all toolkit files and archive completed analyses with their date. Six Forces analyses are most valuable when compared over time: how has supplier power shifted since a key vendor was acquired? Without version control, prior analyses get overwritten or lost, and you cannot track force dynamics across quarters.

Common Mistakes

Selecting market research tools based on feature lists rather than actual data coverage for your specific industry

Correction

A tool that covers 200 industries but has shallow data on yours is less useful than a niche database with deep coverage of your vertical. Before committing to any tool, run a test query for your exact industry and geography. Pull a sample data point you know you will need, such as market share for the top five competitors, and verify it exists, is current, and is at the right granularity. Feature demos and free trials are the time to do this, not after you have paid for an annual subscription and built your workflow around it.

Using vague rating anchors like 'high,' 'medium,' and 'low' without quantitative thresholds

Correction

Vague labels produce unreliable scores because each analyst brings their own mental benchmark. This surfaces as mysterious disagreements during review meetings where two people rated the same force differently and cannot explain why. Fix this by defining observable thresholds: 'Buyer power is rated 4 when the top five customers account for 40-60% of industry revenue and have at least two alternative suppliers.' These thresholds can be approximate, but they must be specific enough that two analysts looking at the same data would arrive within one point of each other.

Building an elaborate, feature-rich template before testing the workflow end to end

Correction

Teams often spend days designing a beautiful template with macros, dropdown menus, and auto-generated charts, only to discover that the workflow breaks at Step 3 because a key data source exports in a format the template cannot consume. The signal to watch for is spending more than two hours on template design before completing one force analysis. Start with a minimal template, plain rows and columns with manual data entry, and run one force through it completely. Then add automation and polish to the parts that actually caused friction during the test.

You will discover that the features you assumed you needed differ from the features that actually save time.

Assigning all six forces to one analyst and expecting consistent depth across all of them

Correction

A single analyst researching all six forces inevitably spends more time on the forces they find interesting or have easier data access for, and rushes through the rest. The tell is when two forces have twelve cited data points each and two others have two. If you have a team, assign one or two forces per person with the same template and deadline. If you are a solo analyst, timebox each force equally (for example, 90 minutes of data collection per force) and do not allow yourself to extend one at the expense of another.

The template's source citation column will make the imbalance visible early if you check it.

Choosing a visualization format that requires data the scoring template does not produce

Correction

This typically happens when the analyst selects a radar chart but the template only records sub-factor scores without a composite formula, or selects a trend-over-time chart but only has one period of data. The result is a last-minute scramble to restructure the template or a hand-drawn chart that bypasses the data entirely. Prevent this by building the visualization template with dummy data during setup (Step 5) and verifying that every data input the chart needs has a corresponding cell in the scoring template's summary tab.

Treating the toolkit as a one-time setup rather than a living document

Correction

After the first analysis, teams file the toolkit away and start from scratch next quarter, losing the calibration, source relationships, and scoring benchmarks they built. The toolkit should be updated after each use: add new sources discovered during research, refine rating anchors that caused confusion, note tools that were dropped and why. A toolkit that improves with each cycle becomes a genuine competitive asset. A toolkit that gets rebuilt each time is just busywork repeated.

Frequently Asked Questions

How do I choose market research tools when I have no budget for paid databases?

Focus on free public sources that cover the most data-intensive forces first. SEC EDGAR and equivalent regulatory filings provide competitor financials. Google Scholar surfaces academic research on industry dynamics. Trade association websites often publish annual market reports. Government statistical agencies (Census Bureau, Eurostat, national statistics offices) provide market sizing data. LinkedIn and Crunchbase cover competitor headcount and funding, which proxy for rivalry intensity. For the complementary products force, platform app stores and integration directories are free and rich. A well-structured free toolkit often covers 70-80% of data needs.

Should I select market research tools before or after defining which forces to prioritize?

Select tools after auditing data requirements for all six forces but before prioritizing any single force. The reason is that your tool selection should ensure minimum viable coverage across all six forces, not deep coverage of two and nothing for the others. Prioritization determines where you spend extra research time, not which forces get tools. If you pick tools based on a pre-selected priority, you risk having no data at all for forces that turn out to be strategically important once the analysis is underway.

How long should selecting and configuring the toolkit take relative to the overall Six Forces analysis?

Plan for 10-15% of total project time. For a two-week analysis, that is one to two days. For a one-week sprint, that is half a day. The common error is spending zero time on setup and losing time throughout the project to ad hoc tool switching and inconsistent scoring. The other error is over-engineering the template for a week before anyone touches actual data. A good rule: if your template has macros that took longer to build than the dry run took to complete, you over-invested in tooling.

Can I use AI tools as part of my market research toolkit for a Six Forces analysis?

Yes, but with strict sourcing discipline. AI tools like ChatGPT with web search, Perplexity, or Gemini are useful for initial landscape scanning, identifying relevant data sources, and summarizing long industry reports. They should not be used as primary data sources themselves because their outputs are not independently verifiable without checking the underlying citations. Use AI to find and summarize sources, then verify and cite the original source in your scoring template. This gives you the speed benefit of AI research without the credibility risk of citing an AI-generated summary as evidence.

How do I handle forces where quantitative data simply does not exist for my industry?

Design qualitative sub-factors with clearly anchored rating scales and require two independent raters. For example, if you cannot find market share data for a fragmented industry, replace the 'market share concentration' sub-factor with 'number of viable competitors within the customer's consideration set,' which you can estimate through customer interviews or review site listings. Document the sub-factor as qualitative in your template and flag it with an 'estimated' confidence level. The key is that the rating anchor must still describe an observable condition, not a feeling. 'We think rivalry is high' is not acceptable. 'We identified 40+ direct competitors offering similar features at similar price points within the same geographic market' is.

Why does my scoring template keep producing similar scores across all six forces?

This is almost always a calibration problem with your rating anchors, not a genuine finding that all forces exert equal pressure. The most common cause is anchors that are too vague, allowing analysts to default to the middle of the scale (3 out of 5) for everything. Check whether your anchors include quantitative thresholds that differentiate a 2 from a 3 and a 3 from a 4. Another cause is using the same sub-factors across forces, like 'number of competitors,' which is meaningful for rivalry but not for buyer power. Each force should have sub-factors specific to the dynamic it measures. Rewrite the anchors with sharper thresholds and rerun the scoring.

How often should I update my toolkit when rerunning the Six Forces analysis quarterly?

Review the toolkit at the start of each cycle but expect to change it minimally. Most updates involve adding or removing a data source because a subscription lapsed or a new one became available, refining one or two rating anchors that caused confusion in the prior round, and updating the visualization template if the audience has changed. A full toolkit overhaul is only warranted when the industry itself has changed structurally, such as a major merger that redefines rivalry, or when the team has turned over significantly and needs re-onboarding. Budget 30-45 minutes for toolkit review at the start of each quarterly cycle.